CAD info

CAD Drawings

2008-08-26T01:45:00.000-07:00

If you want to start drawing on CAD and you feel you don’t have the proper know-how, then first avail yourself of the CADD Primer available with your software or on the Internet. The CADD Primer will explain to you the basics of drawing in CAD.

The CADD Primer will not delve into the functions or features of CAD, rather it will teach you how to manipulate your computer to draw the basics in ellipses, circles arcs, and other two-dimensional figures; that is the base knowledge of any design instrument—the ability to control shape and manipulate space. Another thing you must learn, aside from drawing figures, is how to superimpose text on your CAD drawings. The Primer may provide instructions for this, but getting a feel for the software should get you through it.

CAD drawings closely resemble those penciled in by hand. The smooth renditions of the images are facilitated by thousands of dots per grid. The resulting image is stored as a vector image that stores other information such as style, thickness, and color per dot of the image.

You might find it awkward to use CAD for the first time because it’s not like the usual pen and paper where you directly manipulate the shapes and colors. In CAD, you normally start with drawing a line across your canvas and then tweaking it later on. You start thinking in terms of vector capability and layering. Layers are like invisible sheets that constitute the look of your final drawing in CAD. You can edit one layer and then leave the rest untouched.

Your CAD drawing may be further enhanced when you have learned more shortcuts and tricks that will speed up your drawing. But like most good programs, CAD is very user friendly, and it will relate geometry to you in ways that you will very much appreciate.

CAD Software Comparisons

2008-08-26T01:44:00.000-07:00

There are more than 30 varieties of CAD software available in the market, which are sourced from different software developers. Apart from these, customers also have the option of downloading freeware and shareware available easily on the Internet. Customers who want to buy CAD software should conduct a comparative study analysis to select the most suitable software among available options.

CAD software can be compared using different product criterion such as cost of the software, developer's profile, after sales technical support and future upgrades. This can be done by using an excel spreadsheet or other software. Product analysis software is also available in the form of freeware, which can be used to compare and select the most cost effective CAD software.

CAD software systems are also compared based on features such as two dimensional (2D) or three dimensional (3D), CAD or CAD+CAM, operating system compatibility ( windows, UNIX, Solaris, and SunOS), microprocessor requirements ( Pentium, Celeron), hard disk space & RAM memory requirements, and supported formats(IGES, DXF, STL, SLA, Gerber, HPGL, CadKey & APT, CATIA CL, Excellon, Gerber).

Customer reviews can also be used to compare different CAD software. Reviews are written by CAD software users who describe their experiences about different brands manufactured by different software development companies. A number of websites are completely dedicated to provide information about CAD software reviews, which can be used to gather information on the benefits and drawbacks of different software programs.

After comparing, different brands of CAD software are rated on a scale of one to five, which is commonly known as star ratings. A rating of four and above indicates that the software is good and can be purchased. Software systems that are rated below three usually do not have advanced features and may have inherent defects. Customers who do not have in-depth knowledge about software systems should opt for CAD software that is rated in the range of four to five.

Cheap CAD Software

2008-08-26T01:43:00.000-07:00

Cheap CAD (computer aided design) software is easily available on the Internet in the form of freeware and shareware. These software systems are used for designing mechanical, electrical, and electrical blueprints. They are also used for simulation, drafting, engineering, product analysis and manufacturing.

Cheap CAD software can easily be installed on mainframes, general-purpose workstations, and personal computers. It is compatible with different computer operating systems such as Microsoft windows, UNIX, Solaris, and SunOS. The software enables engineers, architects, and fashion designers to create conceptual drawings for assessment and approval.

Cheap CAD software can be broadly classified into two categories. Basic CAD software that uses two dimensional (2D) imaging is the most commonly used software for drafting services and general-purpose applications. In comparison to these, three dimensional (3D) CAD software is used for high-end applications such as machine shops, product designing, reverse engineering, and complex surfacing. It is the most commonly used software by architects, builders, facility managers, and construction companies. Cheap CAD software also includes specialized products such as CAD file viewers, CAD file converters, CAD file red lining, CAD symbols, and CAD libraries.

Cheap CAD software enables designers to import CAD files, which are required for controlling manufacturing equipment. It is used in mechanical engineering to calculate tool paths and set up machining operations. Tool paths stored in cutter location( CL) format are exported to a postprocessor for conversion to a numerically controlled (NC) program. Many of these programs have text files that incorporate start and stop locations along a grid with X,Y, and Z axis.

Cheap 2D CAD software is used for designing machines such as lathes, routers, lasers, water jets, and plasma tables whereas 3D software is used mostly for designing milling machines. Cheap CAD software can also be used for designing printed circuit board (PCB) and integrated circuit (IC) blueprints

TurboCAD Pro 15

2008-05-26T06:37:00.000-07:00

TurboCAD Pro 15 is the premium design software solution that’s delivered exceptional value to both 2D and 3D users for over 20 years.
TurboCAD Pro’s robust set of 2D drafting and 3D modeling tools enable users to create innovative designs for a wide range of industries and disciplines. TurboCAD also includes several industry-leading technologies, such as Spatial Technology’s ACIS® solid modeling engine, LightWork Design’s photorealistic rendering and lighting engine and material libraries, and Siemens PLM Software’s D-Cubed geometric and dimensional constant engine.
TurboCAD Pro’s incredible flexibility, low learning curve and overall ease of use are hallmarks of this award-winning program. A completely customizable graphical user interface, SEKE’s (Single Entry Key commands), and a Part/History Tree allows for editing of complex designs in any order.
TurboCAD Pro is incredibly compatible with other CAD and graphics programs and formats, supporting import from over 30 file formats and export to over 25 formats. Our DXF and DWG file translators for AutoCAD® are considered some of the best in the industry.
Whether you are a professional mechanical engineer, architect or builder, civil engineer, woodworker, hobbyist or student, TurboCAD has you covered! Plus, there are optional, specialized architectural and mechanical toolsets available for purchase, as well as plug-ins that extend TurboCAD’s capabilities into 3D Animation, Furniture Design, Computer Aided Machining (CAM), and more.

System Requirements:
Minimum:
* Pentium IV Processor
* Microsoft ® Windows XP 512 MB RAM, Microsoft ® Vista 1 GB RAM
* 300 MB of free hard disk space depending on accessory applications installed, 64 MB of swap space
* Super VGA (1024 x768) display
* High Color (16 bit) graphics card
* DVD-ROM drive

Recommended:
* 2 GHz Processor, 2 GB RAM
* 3D Graphics accelerator card
* Wheel mouse
* Internet connection
* Microsoft ® Internet Explorer™ required for Internet registration
* Macromedia ® Flash™ plug-in required for on-line tutorials

2008-05-26T06:17:00.000-07:00

DesignAdvance Systems:
PCB Design
DesignAdvance Systems, a developer of intelligent electronic design automation solutions for printed circuit board (PCB) design, announced the release of CircuitProbe v2.2. The new product enables bidirectional communication between a layout and a PDF of the schematic.
The tool allows designers and engineers to select one or more design elements in the Cadence Allegro Viewer environment or a PDF of the schematic and have the corresponding design elements selected in the other application.
In addition to bidirectional cross-probe between layouts and PDF schematics, CircuitProbe features the following capabilities:
* interactive clustering
* ability to save physical design templates
* population of any Allegro selection set
* ability to verify location of design elements in either application

Animech Technologies:
Communication and Presentation Software
Animech Technologies announced a new release of its aniPart communication and presentation solution designed to streamline tasks associated with the management of product revisions.
The 3D import process in aniPart Studio v3.5 automatically matches old objects with new and decides how the changes to the new will apply to work already invested in the instruction. A Client 3.5 Play/Pause button and a progress bar for actions are included in this latest release as well.
Material developed in aniPart Studio can be published for both online and offline use and viewed with aniPart webClient, which is free for end users

Eurocom:
Mobile Workstation
Eurocom released the M860TU Montebello 15.4-inch mobile workstation, which is based on an Intel Cantiga PM45 chipset and Nvidia's GeForce 9xxx series VGA technology.
The EUROCOM M860TU Notebook PC features SATA-300 hard drives. A choice of LCD displays and an upgradeable NVIDIA GeForce Go 8800M GTX, 9800M GTX, or Quadro FX1600M with up to 1 GB of DDR3 video memory are included as well. Powered by Intel's new line of Mobile Core 2 Duo, Quad Core, and Quad Core Extreme dual-core processor technology, the M860TU also features 320 GB with 7,200 rpm.
The EUROCOM M860TU uses Nvidia MXM (Mobile PCI Express Module) for upgradeability to new graphics technology. By using a mechanical graphics interface in the form of high-performance MXM, Eurocom can introduce a variety of PCI Express graphics solutions quickly, the company states.
Standard ports include four USB 2.0, one DVI for external display, one Firewire IEEE1394a, one RJ-45 for 1 GB LAN, one RJ11 for Modem/Phone, one S/PDIF output, one built-in microphone, and one headphone jack. The EUROCOM M860TU Montebello supports various 32-bit and 64-bit operating systems from Microsoft Vista Business or Ultimate to XP Professional and Linux.

2008-05-25T07:26:00.000-07:00

Why SolidWorks is the best choice for AutoCAD users?
SolidWorks software allows you to test and revise product designs easily, so you can get design work done 20-30% faster. Not only is SolidWorks easy to learn and use, it offers unmatched compatibility with AutoCAD software and other CAD systems.
Going from 2D to 3D is easy:
Design sketches and assembly layouts may represent the first step of a consumer product or machine design; and if they exist in AutoCAD, SolidWorks can use them as the foundation for 3D geometry. For instance, the aforementioned DWG/DXF Import wizard also allows such a file to be imported directly into the SolidWorks sketcher – from there, it can easily be turned into a 3D model. If there are any problems inherent in the drawing or caused by the translation, the SolidWorks Repair tool will automatically fix these problems in the sketcher. In addition, if the drawing contains multiple views, SolidWorks tools will semiautomatically project that 2D geometry into the third dimension.
SolidWorks software includes several tools to simplify the building of assembly layouts. First, SolidWorks deals with imported geometry as separate entities. This makes it easy, for instance, to delete AutoCAD geometry that’s not necessary in building the desired model. It’s also simple to select only the entities that you need, and then use the ability with SolidWorks to automatically copy them into a separate sketch in just two clicks. SolidWorks also simplifies the selection of certain elements via its advanced Selection Filters.

Machine design

2008-04-26T00:11:00.000-07:00

Creation Of New Machines - Machine Design:
A machine is a mechanical device that transmits or modifies energy to an output. Usually, machines are restricted to devices having an unbending or inflexible moving part that helps in performing the valuable work. Tools, or simply devices, not machines having no rigid moving parts.
A machine design is the creation of new and ameliorates machines. A better machine is one which is more economical in the overall cost of production and performance. The process of design is a long and time consuming one. In designing a machine component, it is essential to have a good knowledge of many subjects such as mathematics, engineering mechanics, strength of materials, and most important is engineering drawing.
Classification of machine design
The machine design may be classified as follows:
1. Adaptive design
2. Development design
3. New design
Adaptive design, in this case there is no need of information or knowledge and can be created by designers of ordinary technical training. Only minor modifications or change in the existing designs of the products has to be made by the designer.
Development design, this type of designing needs extensive scientific training and design talent in order to modify the existing designs into a new idea by adopting a new material or different method of manufacture.
New design, this type of design is totally different as this design needs lot of research, technical ability and creative thinking, designers having personal qualities of sufficiently high order can take the work of new design.
The designs depending upon the methods used may be classified as follows:
a) Rational design: depend upon mathematical formulae of principle of mechanics.
b) Empirical design: depend upon empirical formulae.
c) Industrial design: depends upon the production aspects
d) System design: it is a design if any complex mechanical system like a motor car
e) Computer aided design: depends upon the use of computer systems to help in creation. Modification and optimization of a design.

CAM applications

2008-04-26T00:08:00.000-07:00

Computer Aided Manufacturing Applications:
Computer Aided Manufacturing (CAM) refers to an automation process, which accurately converts product design and drawing or the object into a code format, readable by the machine to manufacture the product. Computer aided manufacturing complements the computer aided design (CAD) systems to offer a wide range of applications in different manufacturing fields. CAM evolved from the technology utilized in the Computer Numerical Control (CNC) machines that were used in the early 1950s. CNC involved the use of coded instructions on a punched paper tape and could control single manufacturing functions. CAM controlled computer systems, however, can control a whole set of manufacturing functions simultaneously.
CAM allows work instructions and procedures to be communicated directly to the manufacturing machines. A CAM system controls manufacturing operations performed by robotic milling machines, lathes, welding machines and other industrial tools. It moves the raw material to different machines within the system by allowing systematic completion of each step. Finished products can also be moved within the system to complete other manufacturing operations such as packaging, synthesizing and making final checks and changes.
Some of the major applications of the CAM system are glass working, woodturning, metalworking and spinning, and graphical optimization of the entire manufacturing procedure. Production of the solids of rotation, plane surfaces, and screw threads is done by applying CAM systems. A CAM system allows the manufacturing of three-dimensional solids, using ornamental lathes with greater intricacy and detail. Products such as candlestick holders, table legs, bowls, baseball bats, crankshafts, and camshafts can be manufactured using the CAM system. CAM system can also be applied to the process of diamond turning to manufacture diamond tipped cutting materials. Aspheric optical elements made from glass, crystals, and other metals can also be produced using CAM systems. Computer aided manufacturing can be applied to the fields of mechanical, electrical, industrial and aerospace engineering. Applications such as thermodynamics, fluid dynamics, solid mechanics, and kinematics can be controlled using CAM systems. Other applications such as electromagnetism, ergonomics, aerodynamics, and propulsion and material science may also use computer aided manufacturing.
CAM provides detailed information on Applications of Computer Aided Manufacturing, Cam And Computer Aided Design, Computer Aided Design , Computer Aided Design Scanners and more. Computer Aided Manufacturing is affiliated with computer aided design and manufacturimg.

CAD info

2008-04-26T00:05:00.000-07:00

Computer-Aided Design, CAD, Mechanical CAD, Architectural CAD, Paper CAD conversions,2D 3D modeling:
Not long time back building designs & drawings was a pain in the neck by the hand using the conventional pen and paper on a drafting table. This soon changed with the advent of the desktop computer, which gave rise to Computer Aided Design (CAD). Changes can be made in a jiffy without having to redo the whole drawing, which was earlier a tiresome process.
Now with CAD in picture, which is known as Computer-aided design, you need not fear about many of your drawings that are lost or destroyed, there is a booming service industry, which is at your doorstep to create computerized CAD drawings & designs in 2 Dimension & 3 Dimension of existing buildings.
CAD can be utilized for architectural as well as mechanical services. CAD is a hardware & software combination that caters to architects, engineers and consultants in the real estate & manufacturing industry globally.
CAD can be used for 2D drafting, 3D modeling, animations , interactive presentations, data managements, 2D - 3D CAD modeling & animation, architectural CAD, mechanical CAD, drafting and design, 2D 3D graphics, paper to CAD conversions, structural CAD drawings , 3D visualization.
In Mechanical CAD services it can be utilized for 2D Drafting, 3D modeling, 3D assembly, 2D - 3D sectional views.

AutoCAD DXF

2008-03-10T03:04:00.000-07:00

AutoCAD DXF (Drawing Interchange Format, or Drawing Exchange Format) is a CAD data file format developed by Autodesk for enabling data interoperability between AutoCAD and other programs.
DXF was originally introduced in December 1982 as part of AutoCAD 1.0, and was intended to provide an exact representation of the data in the AutoCAD native file format, DWG (Drawing), for which Autodesk did not — and, as of 2008, does not — publish specifications. Autodesk now publishes specifications on its website for versions of DXF dating from AutoCAD Release 13 (November 1994) to AutoCAD 2008 (March 2007).
Versions of AutoCAD from Release 10 (October 1988) and up support both ASCII and binary forms of DXF. Earlier versions support only ASCII.
As AutoCAD has become more powerful, supporting more complex object types, DXF has become less useful. Certain object types, including ACIS solids and regions, are not documented. Other object types, including AutoCAD 2006's dynamic blocks, and all of the objects specific to the vertical-market versions of AutoCAD, are partially documented, but not well enough to allow other developers to support them.
Almost all significant commercial application software developers, including all of Autodesk's competitors, choose to support DWG as their primary format for AutoCAD data interoperability, using libraries from the Open Design Alliance — a non-profit industry consortium which has reverse-engineered the DWG file format.

2008-03-10T03:03:00.000-07:00

TopSolid:
TopSolid is a 3D computer-aided design (CAD) software which is edited and developed by the company Missler Software. At the outset the software worked on Unix machines whereas today it works exclusively on Windows PCs.
The TopSolid range of software includes a whole family of software: from the more general, mechanical oriented (TopSolid’Design) to job specific solutions: sheet metal (TopSolid’Fold), wood (TopSolid’Wood), toolmaking: TopSolid’Mold for mold makers and TopSolid’Progress for press tool designers. TopSolid also incorporates an integrated Computer-aided_manufacturing (CAM) line of products: Mechanical machining (TopSolid’Cam), sheet metal (TopSolid’PunchCut), wood (TopSolid’WoodCam), wire electroerosion (TopSolid’Wire). TopSolid also incorporates a 2D draft module (TopSolid’Draft) and a structural calculation module (TopSolid’Castor).
TopSolid is, therefore, a CAD/CAM solution based on the geometric modeller ParaSolid. It is, of course, capable of reading and creating files in all available formats as well as in such formats as Catia and ParaSolid.
TopSolid is sold worldwide and has been rated as the 2nd CAD/CAM editor in France behind Dassault Systèmes (software Catia and SolidWorks). It has been rated as the 1st French CAM editor and is ranked among the Top 10 CAD/CAM editors worldwide and is the fastest growing CAD CAM Company in 2007. The speciality of TopSolid'Cam lies in Multi Axis Machining popularly 5 axis machining and Mill Turn, twin Spindle, twin turret Technology.

2008-03-10T02:52:00.000-07:00

Alibre Design:
Alibre Design is a parametric feature-based three-dimensional Solid modeling CAD software created by Alibre, Inc.
Overview:
Alibre Design is a mechanical engineering and design CAD tool capable of creating complex 3D models, assemblies, and 2D drawings. Alibre Design is a parametric, feature-based modeler allowing users to create intelligent 3D design using parameters for dimensions that can be varied at any time, and common engineering features such as holes, chamfers and fillets. Features also incorporate parameters, such as the diameter or radius of a hole, in addition to other inherent attributes such as whether a hole is countersunk or counterbored. Another common property of a hole, or a "cut," which is a feature of arbitrary shape that removes material, is its depth. For instance, a hole or cut can be a "through all" causing it to always pass completely though a part no matter what its thickness.
Product Family:
The Alibre Design product family consists of four products.

*Alibre Design Xpress
* Alibre Design
* Alibre Design Professional
* Alibre Design Expert

AUTO CAD USES

2008-02-19T08:19:00.000-08:00

AutoCAD LT:
AutoCAD LT is a "scaled down" version of AutoCAD. It costs less (approx. $900 USD versus around $4,000 USD for the full AutoCAD). It is also available for purchase at computer stores, unlike AutoCAD which has to be purchased from an official Autodesk dealer. It was developed so Autodesk could have an entry-level CAD package available to compete in that price class. Today AutoCAD LT is marketed as a CAD package for those who only need 2D functionality. Compared to the full edition of AutoCAD, AutoCAD LT lacks several features. Most notably, it has no 3D modeling capabilities (though it has a full suite of 3D viewing functions for looking at 3D models created in other CAD packages) and does not include any programming interfaces, such as support for most 3rd party programs and does not support LISP programs. A full listing of differences is on the Autodesk website. AutoCAD LT originated by taking the codebase of AutoCAD and commenting out substantial portions, which allowed AutoCAD and AutoCAD LT to be developed simultaneously.
AutoCAD Student Versions:
AutoCAD is licensed at a significant discount over commercial retail pricing to qualifying students and teachers, with both a 14 month and perpetual license available. The student version of AutoCAD is functionally identical to the full commercial version, with one exception: DWG files created or edited by a student version have an internal bit-flag set (the "educational flag"). When such a DWG file is printed by any version of AutoCAD (commercial or student), the output will include a plot stamp / banner on all four sides.
Vertical programs:
Autodesk has also developed a few vertical programs, sometimes called Desktops, for discipline-specific enhancements. AutoCAD Architecture (formerly Architectural Desktop), for example, permits architectural designers to draw 3D objects such as walls, doors and windows, with more intelligent data associated with them, rather than simple objects such as lines and circles. The data can be programmed to represent specific architectural products sold in the construction industry, or extracted into a data file for pricing, materials estimation, and other values related to the objects represented. Additional tools allow designers to generate standard 2D drawings, such as elevations and sections, from a 3D architectural model. Similarly, Civil Design, Civil Design 3D, and Civil Design Professional allow data-specific objects to be used, allowing standard civil engineering calculations to be made and represented easily. AutoCAD Mechanical, AutoCAD Electrical, AutoCAD Civil 3D, and AutoCAD Map 3D are other examples of industry-specific CAD applications built on the AutoCAD platform.

AUTO CAD

2008-02-19T08:09:00.000-08:00

AutoCAD:
AutoCAD is a CAD software application for 2D and 3D design and drafting, developed and sold by Autodesk, Inc. Initially released in late 1982, AutoCAD was one of the first CAD programs to run on personal computers, and notably the IBM PC. Most CAD software at the time ran on graphics terminals connected to mainframe computers or mini-computers.
In earlier releases, AutoCAD used primitive entities — such as lines, polylines, circles, arcs, and text — as the foundation for more complex objects. Since the mid-1990s, AutoCAD has supported custom objects through its C++ API. Modern AutoCAD includes a full set of basic solid modeling and 3D tools, but lacks some of the more advanced capabilities of solid modeling applications.
AutoCAD supports a number of application programming interfaces (APIs) for customization and automation. These include AutoLISP, Visual LISP, VBA, .NET and ObjectARX. ObjectARX is a C++ class library, which was also the base for products extending AutoCAD functionality to specific fields, to create products such as AutoCAD Architecture, AutoCAD Electrical, AutoCAD Civil 3D, or third-party AutoCAD-based applications.
AutoCAD's native file format, DWG, and to a lesser extent, its interchange file format, DXF, have become de facto standards for CAD data interoperability. AutoCAD in recent years has included support for DWF, a format developed and promoted by Autodesk for publishing CAD data. In 2006, Autodesk estimated the number of active DWG files to be in excess of one billion. In the past, Autodesk has estimated the total number of DWG files in existence to be more than three billion.
AutoCAD currently runs exclusively on Microsoft desktop operating systems. Versions for Unix and Macintosh were released in the 1980s and 1990s, but these were later dropped. AutoCAD can run on an emulator or compatibility layer like Virtual PC or Wine, keeping in mind the performance issues that can arise when working with 3D objects or large drawings.
AutoCAD and AutoCAD LT are available for German, French, Italian, Spanish, Japanese, Korean, Chinese Simplified (No LT), Chinese Traditional, Russian, Czech, Polish, Hungarian (No LT), Brazilian Portuguese (No LT), Danish, Dutch, Swedish, Finnish, Norwegian and Vietnamese. The extent of localization varies from full translation of the product to documentation only.

CATIA used for CAD

2008-02-19T07:58:00.000-08:00

CATIA:
CATIA (Computer Aided Three dimensional Interactive Application) is a multi-platform CAD/CAM/CAE commercial software suite developed by French company Dassault Systemes and marketed world-wide by IBM. The software was originally intended for the development of Dassault's Mirage fighter jet, but became a runaway success and was subsequently adopted by numerous well known companies world-wide, such as Boeing and IBM. The software was also famously used by architect Frank Gehry in his building of the Guggenheim Museum Bilbao. CATIA is written in the C++ programming language. CATIA is the corner stone of the Dassault Systemes PLM software suite.
Features and capabilities:
Commonly referred to as a 3D Product Lifecycle Management software suite, CATIA supports multiple stages of product development (CAx). The stages range from conceptualization, through design (CAD) and manufacturing (CAM), until analysis (CAE).
CATIA provides an open development architecture through the use of interfaces, which can be used to customize or develop applications. The supporting application programming interfaces are as follows:
*The Fortran and C programming languages for version 4 (V4).
*The Visual Basic and C++ programming languages for version 5 (V5).
These APIs are referred to as CAA for V4 and CAA2 (or CAA V5) for V5. The CAA2 are component object model (COM) like interfaces. They provide integration for products developed on the CATIA suite of software.
Although later versions of CATIA V4 implemented NURBS, version 4 principally used piecewise polynomial surfaces. CATIA V4 uses a non-manifold solid engine.
Catia V5 features a parametric solid/surface-based package which uses NURBS as the core surface representation and has several workbenches that provide KBE support.
As of 2007, the latest release is V5 release 18 (V5R18).
One of the main reasons customers choose CATIA V5 is its ability to seamlessly interact and work in tandem with a host of other applications like Enovia, Smarteam, various CAE Analysis applications etc.
Supported operating systems and platforms:
CATIA V4 is supported for various flavours of Unix - IBM AIX, Hewlett Packard HP-UX, Silicon Graphics IRIX and Sun Microsystems Solaris.Catia V4 and its predecessor versions were also available for IBM MVS and VM/CMS mainframe platforms.
CATIA V5 is provided on Microsoft Windows and the above-mentioned Unixes.

Simulation Types

2008-02-19T07:53:00.000-08:00

Types of Simulations:
There are a wide range of electrical engineering tests that can be performed on a power systems CAD model. These include tests for:
*Short Circuit Analysis
*AC and DC Arc Flash
*Protective Device Coordination
*Cable Pulling
*Power System Reliability
*Electromagnetic Transient Analysis
*Cable Ampacity
*Induction Motor Parameter Estimation
*Transmission Line Parameters
*Advanced Transient
*Power System Optimization
*Advanced Substation Grounding Grid Design
*Advanced Motor Starting
*Voltage Stability and Contingency Analysis.

2008-02-19T07:50:00.000-08:00

Types of Simulations:
There are a wide range of electrical engineering tests that can be performed on a power systems CAD model. These include tests for:
Short Circuit Analysis

AC and DC Arc Flash

Protective Device Coordination

Power Flow

Cable Pulling

Power System Reliability

Electromagnetic Transient Analysis

Cable Ampacity Induction Motor

Parameter Estimation Transmission

Line Parameters

Advanced Transient Power System Optimization Advanced Substation Grounding Grid Design Advanced Motor Starting Voltage Stability and Contingency Analysis

Power Systems CAD

2008-02-19T07:39:00.000-08:00

Power Systems CAD:
Power Systems CAD refers to computer-aided design (CAD) software tools that are used to design and simulate complex electrical power systems.
Such power systems are typically found in mission-critical facilities such as computer data centers, network operations centers, air traffic control systems, transportation networks, power plants, manufacturing facilities, etc. The goal of these systems is to ensure that potential electrical power problems are "engineered-out" of the design, prior to a facility being constructed.
Electrical power systems CAD tools are used by electrical power systems engineers, a distinct discipline of electrical engineering. According to the Institute of Electrical and Electronics Engineers (IEEE), there are 21,000 power systems engineers worldwide focused on improving electrical grids, eliminating blackouts, and reducing electrical accidents.Such engineering expertise is instrumental to preserving the critical power needs of modern digital society, e.g. transportation, communications, computing, etc.
In the United States alone, power systems engineering is a $100 billion industry. Power systems CAD tools are credited with dramatically increasing the productivity, efficiency, and effectiveness of electrical systems designers by virtue of their:
Providing a design foundation that allows power systems to be created quickly Enabling design engineers to test the safety and integrity of their design concepts Allowing design engineers to create a repository if proven design elements that can be reused in future projects Thus power systems CAD software products allow organizations to develop higher-quality power systems designs, with faster turnaround time, than ever before possible.

Power Systems CAD Overview:
The electrical power systems CAD process, frequently called power systems "modeling," typically consists of two distinct stages:
The design stage, in which an electric systems model is created, and The simulation or analysis stage, in which software simulation programs are used to test the integrity of the design; these simulation programs test how the model would behave in real-world operation by checking for specific types of design or operational problems.It is important to note that this is an iterative process, in which simulation results will suggest ways that the design should be modified to increase safety, reliability, and serviceability. At the conclusion of the design effort, organizations will enjoy a far higher degree of confidence in the integrity of their power systems infrastructure than with manually-drawn schematics.
Further, in the case of "Power analytics" systems, the CAD model is also used for on-line diagnostics and predictive maintenance, once the facility is constructed.

SHIP BUILDING

2008-01-29T06:00:00.000-08:00

Ship building:
Shipbuilding is the construction of ships. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, originally called shipwrights, follow a specialized occupation that traces its roots to before recorded history.
Shipbuilding and ship repairs, both commercial and military, are referred to as the "naval sector". The dismantling of ships is called ship breaking. The construction of boats is a similar activity called boat building.
History:

Archaeological evidence indicates that humans arrived on New Guinea at least 60,000 years ago, probably by sea from Southeast Asia during an ice age period when the sea was lower and distances between islands shorter. (See History of Papua New Guinea.) The ancestors of Australian Aborigines and New Guineans went across the Lombok Strait to Sahul by boat over 50,000 years ago.
Evidence from ancient Egypt shows that the early Egyptians already knew how to assemble planks of wood into a watertight hull, using treenails to fasten them together, and pitch for caulking the seams. The "Khufu ship", a 43.6 m long vessel sealed into a pit in the Giza pyramid complex at the foot of the Great Pyramid of Giza in the Fourth Dynasty around 2,500 BC, is a full-size surviving example which may have fulfilled the symbolic function of a solar barque. The ships of the Eighteenth Dynasty were typically about 25 meters (80 ft) in length, and had a single mast, sometimes consisting of two poles lashed together at the top making an "A" shape. They mounted a single square sail on a yard, with an additional spar along the bottom of the sail. These ships could also be oar propelled.
The ships of Phoenicia seems to have been of a similar design. The Greeks and probably others introduced the use of multiple banks of oars for additional speed, and the ships were of a light construction and for speed so they could be carried ashore.
The world's first tidal dock was built in Lothal around 2500 BC during the Harappan civilisation at Lothal near the present day Mangrol harbour on the Gujarat coast in India. Other ports were probably at Balakot and Dwarka. However, it is probable that many small-scale ports, and not massive ports, were used for the Harappan maritime trade.Ships from the harbour at these ancient port cities established trade with Mesopotamia.
The naval history of China stems back to the Spring and Autumn Period (722 BC–481 BC) of the ancient Chinese Zhou Dynasty. The Chinese built large rectangular barges known as 'castle ships', essentially floating fortresses complete with multiple decks with guarded ramparts. They also built ramming vessels like in the Greco-Roman tradition of the trireme, although oar-steered ships in China lost their favor very early on since it was in 1st century China that the stern-mounted rudder was first developed. This was dually met with the introduction of the Han Dynasty junk ship design in the same century. The shipbuilding industry in Imperial China reached its height during the Song Dynasty, Yuan Dynasty, and early Ming Dynasty. During the Song period (960–1279 AD), the onset of establishing China's first official standing navy in 1132 AD and the enormous increase in maritime trade abroad (from Heian Japan to Fatimid Egypt) allowed the shipbuilding industry in provinces like Fujian to thrive like never before. Some of the largest seaports in the world existed in China during this era, including Guangzhou, Quanzhou, and Xiamen.
Viking longships developed from an alternate tradition of clinker-built hulls fastened with leather thongs. Sometime around the 12th century, northern European ships began to be built with a straight sternpost, enabling the mounting of a rudder, which was much more durable than a steering oar held over the side. Development in the Middle Ages favored "round ships", with a broad beam and heavily curved at both ends.
The introduction of cannons onto ships encouraged the development of tumblehome, the inward slant of the abovewater hull, for additional stability (reference?), as well as techniques for strengthening the internal frame. This kind of considerations, as well as the demand for ships capable of operating safely in the open ocean, led to the documentation of design and construction practice in what had previously been a secretive trade, and ultimately the field of naval architecture. Even so, construction techniques changed only very gradually; the ships of the Spanish Armada were internally very similar to those of the Napoleonic Wars over two centuries later.
Iron was gradually adopted in ship construction, initially in small areas needing greater strength, then throughout, although initially copying wooden construction. Isambard Brunel's Great Britain of 1843 was the first radical new design; built entirely of iron, using stringers for strength, inner and outer hulls, and bulkheads to form multiple watertight compartments. Despite her success, many yards only went so far to use composite construction, with wooden timbers laid over an iron frame (the Cutty Sark is so constructed). Steel supplanted wrought iron when it became readily available in the latter half of the 19th century. Wood continued to be favored for the decks, and is still the rule as deckcovering for modern cruise ships.
Shipwrights in England:

During the 16th century Shipwrights in England were so few in number as to be granted direct employment by the Crown. The first list of ‘Master Shipwrights’ appointed ‘by Patent’ was issued by Henry VIII and included ‘John Smyth, Robert Holborn, Richard Bull and James Baker’ (father of Mathew Baker). Peter Pett the son of John was summoned from his place of residence, then at Harwich to work on the King’s Ships at Portsmouth, and in 1543 was granted a wage and fee for life (vadium et feodum). The authority for the letters patent not being by the usual Writ of Privy Seal, but ‘Per Ipsum Regent’, i.e, by ‘direct motion of the King’, Henry VIII.
On the 23 April 1548 Robert Holborn, Smyth and Bull received similar Patents, the very fact of which should be considered of some significance, and it was added as Shipwrights they should instruct others, by reason of their long and good service
Modern shipbuilding:
Design work, also called naval architecture, may be conducted using a ship model basin.
Modern ships, since roughly 1940, have been produced almost exclusively of welded steel. Early welded steel ships used steels with inadequate fracture toughness, which resulted in some ships suffering catastrophic brittle fracture structural cracks (see problems of the Liberty ship). Since roughly 1950, specialized steels such as ABS Steels with good properties for ship construction have been used.
Modern shipbuilding makes considerable use of prefabricated sections; entire multi-deck segments of the hull or superstructure will be built elsewhere in the yard, transported to the building dock or slipway, then lifted into place. This is known as Block Construction. The most modern shipyards pre-install equipment, pipes, electrical cables, and any other components within the blocks, to minimize the effort needed to assemble or install components deep within the hull once it is welded together.
Shipbuilding (which encompasses the shipyards, the marine equipment manufacturers and a large number of service and knowledge providers) is an important and strategic industry in a number of countries around the world. This importance stems from:
The large number of trade persons required directly by the shipyard and also by the supporting industries such as steel mills, engine manufacturers, etc. A nation's need to manufacture and repair its own Navy and vessels that support its primary industries. Historically, the industry has suffered from the absence of global rules and a tendency of (state-supported) over-investment due to the fact that shipyards offer a wide range of technologies, employ a significant number of workers and generate foreign currency income (as the shipbuilding market is dollar-based and a global one). Shipbuilding is therefore an attractive industry for developing nations. Japan used shipbuilding in the 1950s and 1960s to rebuild its industrial structure, Korea made shipbuilding a strategic industry in the 1970s and China is now in the process to repeat these models with large state-supported investments in this industry. As a result the world shipbuilding market suffers from over-capacities, depressed prices (although the industry experienced a price increase in the period 2003–2005 due to strong demand for new ships which was in excess of actual cost increases), low profit margins, trade distortions and wide-spread subsidisation. All efforts to address the problems in the OECD have so far failed, with the 1994 international shipbuilding agreement never entering into force and the 2003–2005 round of negotiations being paused in September 2005 after no agreement was possible.
Where state subsidies have been removed and domestic policies do not provide support, in high cost nations shipbuilding has usually gone into steady, if not rapid, decline. The British shipbuilding industry is one of many examples of this. From a position in the early 1970s where British yards could still build the largest types of sophisticated merchant ships, British shipbuilders today have been reduced to a handful specialising in defence contracts and repair work. In the U.S.A., the Jones Act (which places restrictions on the ships that can be used for moving domestic cargoes) has meant that merchant shipbuilding has continued, but such protection has failed to penalise shipbuilding inefficiencies. The consequence of this is newbuilding contract prices that are far higher than those of any other nation building oceangoing ships.
Thanks to the superior quality and productivity of its shipyards, South Korea is the world's largest shipbuilding nation in terms of tonnage and numbers of vessels built, in spite of high labour costs. China is currently the third largest shipbuilding country and poised to overtake Japan in the near future.

AUTOMOBILE ENGINEERING

2008-01-29T05:34:00.000-08:00

Automobile:
"Car" redirects here. For other uses, see Car (disambiguation).An automobile (via French from Greek auto, self and Latin mobilis moving, a vehicle that moves itself rather than being moved by another vehicle or animal) or motor car (usually shortened to just car) is a wheeled passenger vehicle that carries its own motor. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally for the transport of people rather than goods.However, the term is far from precise because there are many types of vehicles that do similar tasks.
There were 590 million passenger cars worldwide (roughly one car for every eleven people) as of 2002
History:
Main article: History of the automobileAlthough Nicolas-Joseph Cugnot is often credited with building the first self-propelled mechanical vehicle or automobile in about 1769, this claim is disputed by some, who doubt Cugnot's three-wheeler ever ran, while others claim Ferdinand Verbiest, a member of a Jesuit mission in China, built the first steam powered car around 1672. In either case François Isaac de Rivaz, a Swiss inventor, designed the first internal combustion engine which was fuelled by a mixture of hydrogen and oxygen and used it to develop the world's first vehicle to run on such an engine. The design was not very successful, as was the case with Samuel Brown, Samuel Morey, and Etienne Lenoir who each produced vehicles powered by clumsy internal combustion engines.
In November 1881 French inventor Gustave Trouvé demonstrated a working three-wheeled automobile. This was at the International Exhibition of Electricity in Paris.
An automobile powered by an Otto gasoline engine was built in Mannheim, Germany by Karl Benz in 1885 and granted a patent in January of the following year under the auspices of his major company, Benz & Cie. which was founded in 1883.
Although several other German engineers (including Gottlieb Daimler, Wilhelm Maybach, and Siegfried Marcus) were working on the problem at about the same time, Karl Benz is generally acknowledged as the inventor of the modern automobile.In 1879 Benz was granted a patent for his first engine, designed in 1878. Many of his other inventions made the use of the internal combustion engine feasible for powering a vehicle and in 1896, Benz designed and patented the first internal combustion flat engine.
Approximately 25 Benz vehicles were built and sold before 1893, when his first four-wheeler was introduced. They were powered with four-stroke engines of his own design. Emile Roger of France, already producing Benz engines under license, now added the Benz automobile to his line of products. Because France was more open to the early automobiles, more were built and sold in France through Roger than Benz sold in Germany.
Daimler and Maybach founded Daimler Motoren Gesellschaft (Daimler Motor Company, DMG) in Cannstatt in 1890 and under the brand name, Daimler, sold their first automobile in 1892. By 1895 about 30 vehicles had been built by Daimler and Maybach, either at the Daimler works or in the Hotel Hermann, where they set up shop after falling out with their backers. Benz and Daimler seem to have been unaware of each other's early work and worked independently.
Daimler died in 1900 and later that year, Maybach designed a model named Daimler-Mercedes, special-ordered by Emil Jellinek. Two years later, a new model DMG automobile was produced and named Mercedes after the engine. Maybach quit DMG shortly thereafter and opened a business of his own. Rights to the Daimler brand name were sold to other manufacturers.
Karl Benz proposed co-operation between DMG and Benz & Cie. when economic conditions began to deteriorate in Germany following the First World War, but the directors of DMG refused to consider it initially. Negotiations between the two companies resumed several years later and in 1924 they signed an Agreement of Mutual Interest valid until the year 2000. Both enterprises standardized design, production, purchasing, sales, and advertising—marketing their automobile models jointly—although keeping their respective brands. On June 28, 1926, Benz & Cie. and DMG finally merged as the Daimler-Benz company, baptizing all of its automobiles Mercedes Benz honoring the most important model of the DMG automobiles, the Maybach design later referred to as the 1902 Mercedes-35hp, along with the Benz name. Karl Benz remained a member of the board of directors of Daimler-Benz until his death in 1929.
In 1890, Emile Levassor and Armand Peugeot of France began producing vehicles with Daimler engines, and so laid the foundation of the motor industry in France. The first American car with a gasoline internal combustion engine supposedly was designed in 1877 by George Selden of Rochester, New York, who applied for a patent on an automobile in 1879. In Britain there had been several attempts to build steam cars with varying degrees of success with Thomas Rickett even attempting a production run in 1860.Santler from Malvern is recognized by the Veteran Car Club of Great Britain as having made the first petrol-powered car in the country in 1894 followed by Frederick William Lanchester in 1895 but these were both one-offs.The first production vehicles came from the Daimler Motor Company, founded by Harry J. Lawson in 1896, and making their first cars in 1897.
In 1892, German engineer Rudolf Diesel got a patent for a "New Rational Combustion Engine". In 1897 he built the first Diesel Engine.In 1895, Selden was granted a United States patent (U.S. Patent 549,160 ) for a two-stroke automobile engine, which hindered more than encouraged development of autos in the United States. Steam, electric, and gasoline powered autos competed for decades, with gasoline internal combustion engines achieving dominance in the 1910s.
Although various pistonless rotary engine designs have attempted to compete with the conventional piston and crankshaft design, only Mazda's version of the Wankel engine has had more than very limited success.
Production:

The large-scale, production-line manufacturing of affordable automobiles was debuted by Ransom Olds at his Oldsmobile factory in 1902. This concept was then greatly expanded by Henry Ford, beginning in 1914.
As a result, Ford's cars came off the line in fifteen minute intervals, much faster than previous methods, increasing production by seven to one (requiring 12.5 man-hours before, 1 hour 33 minutes after), while using less manpower.It was so successful, paint became a bottleneck. Only Japan black would dry fast enough, forcing the company to drop the variety of colors available before 1914, until fast-drying Duco lacquer was developed in 1926.In 1914, an assembly line worker could buy a Model T with four months' pay.
Ford's complex safety procedures—especially assigning each worker to a specific location instead of allowing them to roam about—dramatically reduced the rate of injury. The combination of high wages and high efficiency is called "Fordism," and was copied by most major industries. The efficiency gains from the assembly line also coincided with the take off of the United States. The assembly line forced workers to work at a certain pace with very repetitive motions which led to more output per worker while other countries were using less productive methods.
In the automotive industry, its success was dominating, and quickly spread worldwide. Ford France and Ford Britain in 1911, Ford Denmark 1923, Ford Germany 1925; in 1921, Citroen was the first native European manufactuer to adopt it. Soon, companies had to have assembly lines, or risk going broke; by 1930, 250 companies which did not had disappeared.
Development of automotive technology was rapid, due in part to the hundreds of small manufacturers competing to gain the world's attention. Key developments included electric ignition and the electric self-starter (both by Charles Kettering, for the Cadillac Motor Company in 1910-1911), independent suspension, and four-wheel brakes.
Since the 1920s, nearly all cars have been mass-produced to meet market needs, so marketing plans have often heavily influenced automobile design. It was Alfred P. Sloan who established the idea of different makes of cars produced by one company, so buyers could "move up" as their fortunes improved.
Reflecting the rapid pace of change, makes shared parts with one another so larger production volume resulted in lower costs for each price range. For example, in the 1930s, LaSalles, sold by Cadillac, used cheaper mechanical parts made by Oldsmobile; in the 1950s, Chevrolet shared hood, doors, roof, and windows with Pontiac; by the 1990s, corporate drivetrains and shared platforms (with interchangeable brakes, suspension, and other parts) were common. Even so, only major makers could afford high costs, and even companies with decades of production, such as Apperson, Cole, Dorris, Haynes, or Premier, could not manage: of some two hundred carmakers in existence in 1920, only 43 survived in 1930, and with the Great Depression, by 1940, only 17 of those were left.
In Europe, much the same would happen. Morris set up its production line at Cowley in 1924, and soon outsold Ford, while beginning in 1923 to follow Ford's practise of vertical integration, buying Hotchkiss (engines), Wrigley (gearboxes), and Osberton (radiators), for instance, as well as competitors, such as Wolseley: in 1925, Morris had 41% of total British car production. Most British small-car assemblers, from Autocrat to Meteorite to Seabrook, to name only three, had gone under. Citroen did the same in France, coming to cars in 1919; between them and the cheap cars in reply, Renault's 10CV and Peugeot's 5CV, they produced 550000 cars in 1925, and Mors, Hurtu, and others could not compete.Germany's first mass-manufactured car, the Opel 4PS Laubfrosch (Tree Frog), came off the line at Russelsheim in 1924, soon making Opel the top car builder in Germany, with 37.5% of the market
Fuel and propulsion technologies:
Most automobiles in use today are propelled by gasoline (also known as petrol) or diesel internal combustion engines, which are known to cause air pollution and are also blamed for contributing to climate change and global warming.Increasing costs of oil-based fuels and tightening environmental law and restrictions on greenhouse gas emissions are propelling work on alternative power systems for automobiles. Efforts to improve or replace these technologies include hybrid vehicles, electric vehicles and hydrogen vehicles.
Safety:
Road traffic injuries represent about 25% of worldwide injury-related deaths (the leading cause) with an estimated 1.2 million deaths (2004) each year.
Automobile accidents are almost as old as automobiles themselves. Early examples include Mary Ward, who became one of the first documented automobile fatalities in 1869 in Parsonstown, Ireland,and Henry Bliss, one of the United State's first pedestrian automobile casualties in 1899 in New York.
Cars have many basic safety problems - for example, they have human drivers who can make mistakes, wheels that can lose traction when braking, turning or acceleration forces are too high, and mechanical systems subject to failure. Collisions can have very serious or fatal consequences. Some vehicles have a high center of gravity and therefore an increased tendency to roll over.
Early safety research focused on increasing the reliability of brakes and reducing the flammability of fuel systems. For example, modern engine compartments are open at the bottom so that fuel vapors, which are heavier than air, vent to the open air. Brakes are hydraulic and dual circuit so that a total braking failure is very rare. Systematic research on crash safety started[citation needed] in 1958 at Ford Motor Company. Since then, most research has focused on absorbing external crash energy with crushable panels and reducing the motion of human bodies in the passenger compartment. This is reflected in most cars produced today.
Significant reductions in death and injury have come from the addition of Safety belts and laws in many countries to require vehicle occupants to wear them. Airbags and specialised child restraint systems have improved on that. Structural changes such as side-impact protection bars in the doors and side panels of the car mitigate the effect of impacts to the side of the vehicle. Many cars now include radar or sonar detectors mounted to the rear of the car to warn the driver if he or she is about to reverse into an obstacle or a pedestrian. Some vehicle manufacturers are producing cars with devices that also measure the proximity to obstacles and other vehicles in front of the car and are using these to apply the brakes when a collision is inevitable. There have also been limited efforts to use heads up displays and thermal imaging technologies similar to those used in military aircraft to provide the driver with a better view of the road at night.
There are standard tests for safety in new automobiles, like the EuroNCAP and the US NCAP tests.There are also tests run by organizations such as IIHS and backed by the insurance industry.
Despite technological advances, there is still significant loss of life from car accidents: About 40,000 people die every year in the United States, with similar figures in European nations. This figure increases annually in step with rising population and increasing travel if no measures are taken, but the rate per capita and per mile traveled decreases steadily. The death toll is expected to nearly double worldwide by 2020. A much higher number of accidents result in injury or permanent disability. The highest accident figures are reported in China and India. The European Union has a rigid program to cut the death toll in half by 2010, and member states have started implementing measures.
Automated control has been seriously proposed and successfully prototyped. Shoulder-belted passengers could tolerate a 32 g emergency stop (reducing the safe inter-vehicle gap 64-fold) if high-speed roads incorporated a steel rail for emergency braking. Both safety modifications of the roadway are thought to be too expensive by most funding authorities, although these modifications could dramatically increase the number of vehicles able to safely use a high-speed highway. This makes clear the often-ignored fact road design and traffic control also play a part in car wrecks; unclear traffic signs, inadequate signal light placing, and poor planning (curved bridge approaches which become icy in winter, for example), also contribute
Economics and impacts:
Cost and benefits of ownership:
The costs of automobile ownership, which may include the cost of: acquiring the vehicle, repairs, maintenance, fuel, depreciation, parking fees, tire replacement, taxes and insurance,are weighed against the cost of the alternatives, and the value of the benefits - perceived and real - of vehicle ownership. The benefits may include personal freedom, mobility, independence and convenience.
Cost and benefits to society:
Similarly the costs to society of encompassing automobile use, which may include those of: maintaining roads, pollution, public health, health care, and of disposing of the vehicle at the end of its life, can be balanced against the value of the benefits to society that automobile use generates. The societal benefits may include: economy benefits, such as job and wealth creation, of automobile production and maintenance, transportation provision, society wellbeing derived from leisure and travel opportunities, and revenue generation from the tax opportunities. The ability for humans to move rapidly from place to place has far reaching implications for the nature of our society. People can now live far from their workplaces, the design of cities can be determined as much by the need to get vehicles into and out of the city as the nature of the buildings and public spaces within the city
Impacts on society and environment:
Transportation is a major contributor to air pollution in most industrialised nations. According to the American Surface Transportation Policy Project nearly half of all Americans are breathing unhealthy air. Their study showed air quality in dozens of metropolitan areas has got worse over the last decade. In the United States the average passenger car emits 11,450 lbs (5 tonnes) of carbon dioxide, along with smaller amounts of carbon monoxide, hydrocarbons, and nitrogen. Residents of low-density, residential-only sprawling communities are also more likely to die in car collisions, which kill 1.2 million people worldwide each year, and injure about forty times this number. Sprawl is more broadly a factor in inactivity and obesity, which in turn can lead to increased risk of a variety of diseases.
Improving the positive and reducing the negative impacts:Fuel taxes may act as an incentive for the production of more efficient, hence less polluting, car designs (e.g. hybrid vehicles) and the development of alternative fuels. High fuel taxes may provide a strong incentive for consumers to purchase lighter, smaller, more fuel-efficient cars, or to not drive. On average, today's automobiles are about 75 percent recyclable, and using recycled steel helps reduce energy use and pollution. In the United States Congress, federally mandated fuel efficiency standards have been debated regularly, passenger car standards have not risen above the 27.5 miles per gallon standard set in 1985. Light truck standards have changed more frequently, and were set at 22.2 miles per gallon in 2007. Alternative fuel vehicles are another option that is less polluting than conventional petroleum powered vehicles.
Future car technologies:
Automobile propulsion technology under development include gasoline/electric and plug-in hybrids, battery electric vehicles, hydrogen cars, biofuels and various alternative fuels.Research into future alternative forms of power include the development of fuel cells, Homogeneous Charge Compression Ignition (HCCI), stirling engines, and even using the stored energy of compressed air or liquid nitrogen.New materials which may replace steel car bodies include duraluminum, fiberglass, carbon fiber, and carbon nanotubes.Telematics technology is allowing more and more people to share cars, on a pay-as-you-go basis, through such schemes as City Car Club in the UK, Mobility in mainland Europe, and Zipcar in the US.

CONSTRUCTION ENGINEERING

2008-01-24T05:32:00.000-08:00

Construction:
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of multitasking. Normally the job is managed by the construction manager and supervised by the project manager, design engineer or project architect.
For the successful execution of a project, effective planning is essential. Those involved with the design and execution of the infrastructure in question must consider the environmental impact of the job, the successful scheduling, budgeting, site safety, availability of materials, logistics, inconvenience to the public caused by construction delays, preparing tender documents, etc
Types of construction projects:In general, there are three types of construction:
Building construction Heavy/highway construction Industrial construction Each type of construction project requires a unique team to plan, design, construct, and maintain the project.
Building construction:
Building construction is the process of adding structure to real property. The vast majority of building construction projects are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, and design team for the entire project. However, all building construction projects include some elements in common - design, financial, and legal considerations. Many projects of varying sizes reach undesirable end results, such as structural collapse, cost overruns, and/or litigatios reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.
Building construction is procured privately or publicly utilizing various delivery methodologies, including hard bid, negotiated price, traditional, management contracting, construction management-at-risk, design & build and design-build bridging.
ProcurementProcurement describes the merging of activities undertaken by the client to obtain a building. There are many different methods of construction procurement; however the three most common types of procurement are:
Traditional (Design-bid-build) Design and Build Management Contracting

Traditional:
This is the most common method of construction procurement and is well established and recognised. In this arrangement, the architect or engineer acts as the project coordinator. His or her role is to design the works, prepare the specifications and produce construction drawings, administer the contract, tender the works, and manage the works from inception to completion. There are direct contractual links between the architect's client and the main contractor. Any subcontractor will have a direct contractual relationship with the main contractor. it is a stipulated price contract type of method.here, design risk is allocated to owner and cost risk is allocated to contractor
Design and build:
This approach has become more common in recent years and includes an entire completed package, including fixtures, fittings and equipment where necessary, to produce a completed fully functional building. In some cases, the Design and Build (D & B) package can also include finding the site, arranging funding and applying for all necessary statutory consents.
The owner produces a list of requirements for a project, giving an overall view of the project's goals. Several D&B contractors present different ideas about how to accomplish these goals. The owner selects the ideas (s)he likes best and hires the appropriate contractor. Often, it is not just one contractor, but a consortium of several contractors working together. Once a contractor (or a consortium) has been hired, they begin building the first phase of the project. As they build phase 1, they design phase 2. This is in contrast to a design-bid-build contract, where the project is completely designed by the owner, then bid on, then completed.
Kent Hansen, director of engineering for the National Asphalt Pavement Association (NAPA), pointed out that state departments of transportation (DOTs) usually use design build contracts as a way of getting projects done when states don't have the resources. In DOTs, design build contracts are usually used for very large projects
Management procurement systems:
In this arrangement the client plays an active role in the procurement system by entering into separate contracts with the designer (architect or engineer), the construction manager, and individual trade contractors. The client takes on the contractual role, while the construction or project manager provides the active role of managing the separate trade contracts, and ensuring that they all work smoothly and effectively together.
Management procurement systems are often used to speed up the procurement processes, allow the client greater flexibility in design variation throughout the contract, the ability to appoint individual work contractors, separate contractual responsibility on each individual throughout the contract, and to provide greater client control
Residential construction:More and more families are looking into building their own homes, or contracting to have them built. Construction practices, technologies, and resources conform to state and local building codes.
Heavy/Highway construction:Heavy/highway construction is the process adding infrastructure to our built environment. Owners of these projects are usually government agencies, either at the national or local level. As in building construction, heavy/highway construction has design, financial, and legal considerations, however these projects are not usually undertaken for-profit, but to service the public interest. However, heavy/highway construction projects are also undertaken by large private corporations, including, among others, the golf courses, harbors, power companies, railroads, and mines, who undertake the construction of access roads, dams, railroads, general site grading, and massive earthwork projects. As in building construction, the owner will assemble a team to create an overall plan to ensure that the goals of the project are met.
Authority having jurisdiction:In construction, the authority having jurisdiction (AHJ) is the governmental agency or subagency which regulates the construction process. In most cases, this is the municipality in which the building is located. However, construction performed for supra-municipal authorities are usually regulated directly by the owning authority, which becomes the AHJ.
During the planning of a building, the zoning and planning boards of the AHJ will review the overall compliance of the proposed building with the municipal General Plan and zoning regulations. Once the proposed building has been approved, detailed civil, architectural, and structural plans must be submitted to the municipal building department (and sometimes the public works department) to determine compliance with the building code and sometimes for fit with existing infrastructure. Often, the municipal fire department will review the plans for compliance with fire-safety ordinances and regulations.
Before the foundation can be dug, contractors are typically required to notify utility companies, either directly or through a company such as Dig Safe to ensure that underground utility lines can be marked. This lessens the likelihood of damage to the existing electrical, water, sewage, phone, and cable facilities, which could cause outages and potentially hazardous situations. During the construction of a building, the municipal building inspector inspects the building periodically to ensure that the construction adheres to the approved plans and the local building code. Once construction is complete and a final inspection has been passed, an occupancy permit may be issued.
An operating building must remain in compliance with the fire code. The fire code is enforced by the local fire department.
Any changes made to a building including its use, expansion, its structural integrity, and fire protection items, require acceptance by the AHJ. Anything affecting basic safety functions, no matter how small they may appear, may require the owner to apply for a building permit, to ensure proper review of the contemplated changes against the building code.
Routes into construction careersThere are several routes to the different careers within the construction industry. Craft industries offer jobs where employees train while they work through apprenticeships and other training schemes. Another way, where many construction staff have found success, is through recruitment agencies.
Technical occupations in the UK require GCSE qualifications or vocational equivalents, either initially or through on the job apprenticeship training. One example is that of Quantity Surveying. Quantity Surveyors are effectively cost managers within the construction industry and may be: (1) employed by Chartered Surveyor practices (referred to often as "PQS" derived from the term Private Quantity Surveyor) who normally represent the client's interest and liaise with the Architect on the client's team, preparing cost plans, preparing tender documentation, giving cost advice on variations, preparing monthly valuation payments to the contractor, agreeing the final account with the contractor, generally looking after the client's interests (although the role can be referred to within some standard forms of contract as being a neutral role to value 'the' costs of the project), in practice it tends to be looking after the client's interests primarily; or (2) employed by Main Contractors, in which role they manage the contractor's costs, place subcontract orders, make payments to subcontractors, claim monthly valuations from the client's surveyor (Private QS or "PQS"), cost manage variations, prepare internal cost reports to senior management and directors, generally managing the project commercially and protect the contractor's interests contractually. Contractual aspects such as delays and extensions of time issues are also within the remit of the Quantity Surveyor (QS); or (3) employed by Subcontractors, in which role they carry out a similar function to Main Contractor's QS's. The main difference is that they are normally submitting monthly valuation claims for payment to the Main Contractor, whereas the Manin Contractor claims from the client's Surveyor (usually a Chartered Surveyor practice or Private QS "PQS"). Large subcontractors may also employ sub-subcontractors, thereby making the QS role similar in the cost management role, including placing sub-contract orders (to sub-subcontractors), valuing and claiming variations, preparing cost reports to senior management, etc; or (4) employed by Local Authorities (local Councils, etc), whereby the role is broadly similar to that of private practice surveyors in cost managing project from the funding client's perspective (in this case the Local Authority council within which they are employed), dealing usually with main contractors; or (5) employed by Developers; whereby the role may be a mixture of the role of a client's surveyor (the funding client being the developer in this case) mixed with that of a main contractor in possibly employing package sub-contractors directly Other information: The most recognised body for surveyors in construction is the Royal Institution of Chartered Surveyors (the 'RICS'). It is more common for a private practice surveyor or local authority employed surveyor to be a member of the RICS, though RICS qualified surveyors do work within main contractors and sub-contractors (the writer of this Quantity Surveyor segment qualified RICS within private practice working on the client's side, then migrated over to work for a large sub-contractor. Such cross-overs are quite common between client's side and contracting). Quantity Surveying offers a great diversity of roles and in career path, working on a variety of projects and within different areas and facets of the construction industry. The qualification of "Chartered Quantity Surveyor" has been superseded as the RICS rules have replaced this with simply "Chartered Surveyor" (except those existing Chartered QS's who registered to keep the Chartered QS title by a date now passed), and Chartered Quantity Surveyor practices have now largely adopted the title of "Construction Cost Consultants" and having the right to call themselves simply "Chartered Surveyors" - though still often referred to in the UK construction industry as "PQS's". It is also possible for Construction Cost Consultant practices to be occasionally employed by local authorities, contractors or subcontractors, on a particular construction project although not if they are already employed as surveyors for the same construction project.
As well as the role of Quantity Surveyor, other professions within the UK construction industry are for example: Architect, Engineer, Project Manager, Planner, Safety Officer. These roles may be in 'Building' (buildings such as Offices, Shopping Centres, Housing); or 'Civil Engineering' (structures such as Bridges, Dams, Motorways/Roads/Highways, Harbours/Ferry Terminals). While projects such as construction of new Power Stations or Naval Bases may comprise a combination of both 'building' and 'civil engineering'.
Graduate roles in the construction industry are filled by people with at least a foundation degree in subjects such as civil engineering, building and construction management. Graduates often receive specialised positions and gain qualifications such as chartered status.
Industrial construction:Industrial construction, though a relatively small part of the entire construction industry, is a very important component. Owners of these projects are usually large, for-profit, industrial corporations. These corporations can be found in such industries as medicine, petroleum, chemical, power generation, manufacturing, etc. Processes in these industries require highly specialized expertise in planning, design, and construction. As in building and heavy/highway construction, this type of construction requires a team of individuals to ensure a successful project.
Design team:
In the modern industrialized world, construction usually involves the translation of paper or computer based designs into reality. A formal design team may be assembled to plan the physical proceedings, and to integrate those proceedings with the other parts. The design usually consists of drawings and specifications, usually prepared by a design team including architects, interior designers, surveyors, civil engineers, cost engineers (or quantity surveyors), mechanical engineers, electrical engineers, structural engineers, and fire protection engineers.The design team is most commonly employed by (i.e. in contract with) the property owner. Under this system, once the design is completed by the design team, a number of construction companies or construction management companies may then be asked to make a bid for the work, either based directly on the design, or on the basis of drawings and a bill of quantities provided by a quantity surveyor. Following evaluation of bids, the owner will typically award a contract to the lowest responsible bidder.
The modern trend in design is toward integration of previously separated specialties, especially among large firms. In the past, architects, interior designers, engineers, developers, construction managers, and general contractors were more likely to be entirely separate companies, even in the larger firms. Presently, a firm that is nominally an "architecture" or "construction management" firm may have experts from all related fields as employees, or to have an associated company that provides each necessary skill. Thus, each such firm may offer itself as "one-stop shopping" for a construction project, from beginning to end. This is designated as a "design Build" contract where the contractor is given a performance specification, and must undertake the project from design to construction, while adhering to the performance specifications.
Several project structures can assist the owner in this integration, including design-build, partnering, and construction management. In general, each of these project structures allows the owner to integrate the services of architects, interior designers, engineers, and constructors throughout design and construction. In response, many companies are growing beyond traditional offerings of design or construction services alone, and are placing more emphasis on establishing relationships with other necessary participants through the design-build process.
The increasing complexity of construction projects creates the need for design professionals trained in all phases of the project's life-cycle and develop an appreciation of the building as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. Building engineering is an emerging discipline that attempts to meet this new challenge.
Financial advisors:Many construction projects suffer from preventable financial problems. Underbids ask for too little money to complete the project. Cash flow problems exist when the present amount of funding cannot cover the current costs for labor and materials, and because they are a matter of having sufficient funds at a specific time, can arise even when the overall total is enough. Fraud is a problem in many fields, but is notoriously prevalent in the construction field. Financial planning for the project is intended to ensure that a solid plan, with adequate safeguards and contingency plans, is in place before the project is started, and is required to ensure that the plan is properly executed over the life of the project.
Mortgage bankers, accountants, and cost engineers are likely participants in creating an overall plan for the financial management of the building construction project. The presence of the mortgage banker is highly likely even in relatively small projects, since the owner's equity in the property is the most obvious source of funding for a building project. Accountants act to study the expected monetary flow over the life of the project, and to monitor the payouts throughout the process. Cost engineers apply expertise to relate the work and materials involved to a proper valuation. Cost overruns with government projects have occurred when the contractor was able to identify change orders or changes in the project resulting in large increases in cost, which are not subject to competition by other firm as they have already been eliminated from consideration after the initial bid.
Large projects can involve highly complex financial plans. As portions of a project are completed, they may be sold, supplanting one lender or owner for another, while the logistical requirements of having the right trades and materials available for each stage of the building construction project carries forward. In many English speaking countries, but not the United States, projects typically use quantity surveyors

CIVIL ENGINEERING

2008-01-24T05:11:00.000-08:00

Civil engineering:
Civil engineering is a professional engineering discipline that deals with the design, construction and maintenance of the physical and natural built environment, including works such as bridges, roads, canals, dams and building. Civil engineering is the oldest engineering discipline after military engineering, and it was defined to distinguish it from military engineering.It is traditionally broken into several sub-disciplines including municipal engineering, environmental engineering, geotechnical engineering, structural engineering, transportation engineering, water resources engineering, materials engineering, coastal engineering, surveying, and construction engineering.
Contents :1 History of the civil engineering profession 2 History of the science of civil engineering 3 The civil engineer 3.1 Education and licensure 3.2 Careers 4 Sub-disciplines 4.1 Construction engineering 4.2 Environmental engineering 4.3 Geotechnical engineering 4.4 Hydraulic engineering 4.5 Materials science 4.6 Structural engineering 4.7 Surveying 4.8 Transportation engineering 5 See also 6 Footnotes 7 References 8 External links
History of the civil engineering profession:Engineering has been an aspect of life since the beginnings of human existence. Civil engineering might be considered properly commencing between 4000 and 2000 BC in Ancient Egypt and Mesopotamia when humans started to abandon a nomadic existence, thus causing a need for the construction of shelter. During this time, transportation became increasingly important leading to the development of the wheel and sailing. The construction of Pyramids in Egypt (circa 2700-2500 BC) might be considered the first instances of large structure constructions. Other ancient historic civil engineering constructions include the Parthenon by Iktinos in Ancient Greece (447-438 BC), the Appian Way by Roman engineers (c. 312 BC), and the Great Wall of China by General Meng T'ien under orders from Ch'in Emperor Shih Huang Ti (c. 220 BC).
Until modern times there was no clear distinction between civil engineering and architecture, and the term engineer and architect were mainly geographical variations referring to the same person, often used interchangeably.In the 18th century, the term civil engineering began to be used to and exchange, and in the construction of ports, harbours, moles, breakwaters and lighthouses, and in the art of distinguish it from military engineering.
The first self-proclaimed civil engineer was John Smeaton who constructed the Eddystone Lighthouse. In 1771 Smeaton and some of his colleagues formed the Smeatonian Society of Civil Engineers, a group of leaders of the profession who met informally over dinner. Though there was evidence of some technical meetings, it was little more than a social society.
In 1818 the Institution of Civil Engineers was founded in London, and in 1820 the eminent engineer Thomas Telford became its first president. The institution received a Royal Charter in 1828, formally recognising civil engineering as a profession. Its charter defined civil engineering as:
“ "...the art of directing the great sources of power in nature for the use and convenience of man, as the means of production and of traffic in states, both for external and internal trade, as applied in the construction of roads, bridges, aqueducts, canals, river navigation and docks for internal intercourse navigation by artificial power for the purposes of commerce, and in the construction and application of machinery, and in the drainage of cities and towns." ”
The first degree in Civil Engineering in the United States was awarded by Rensselaer Polytechnic Institute in 1835.
History of the science of civil engineering:
Civil engineering is the application of physical and scientific principles, and its history is intricately linked to advances in understanding of physics and mathematics throughout history. Because civil engineering is a wide ranging profession, including several separate specialized sub-disciplines, its history is linked to knowledge of structures, materials science, geology, soils, hydrology, environment, mechanics and other fields.
Throughout ancient and medieval history most architectural design and construction was carried out by artisans, such as stone masons and carpenters, rising to the role of master builder. Knowledge was retained in guilds and seldom supplanted by advances. Structures, roads and infrastructure that existed were repetitive, and increases in scale were incremental.
One of the earliest examples of a scientific approach to physical and mathematical problems applicable to civil engineering is the work of Archimedes in the 3rd century BC, including Archimedes Principle, which underpins our understanding of buoyancy, and practical solutions such as Archimedes Screw.
The civil engineer:
Education and licensureCivil engineers typically possess an academic degree with a major in civil engineering. The length of study for such a degree is usually four or five years and the completed degree is usually designated as a Bachelor of Engineering, though some universities designate the degree as a Bachelor of Science. The degree generally includes units covering physics, mathematics, project management, design and specific topics in civil engineering. Initially such topics cover most, if not all, of the sub-disciplines of civil engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree.
Graduates can choose to pursue a postgraduate degree such as a Master of Engineering, Master of Science, or a Doctor of Philosophy in Engineering. The Master of Engineering degree may consist of either research, coursework or a mixture of the two. The Doctor of Philosophy consists of a significant research component and is often viewed as the entry point to academia. In the United Kingdom and various other European countries, the Master of Engineering is the minimum acceptable qualification for accreditation by the relevant professional bodies, and is often included as an extra year on the undergraduate engineering degree.
In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience and exam requirements) before being certified. Once certified, the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa), Chartered Engineer (in most Commonwealth countries), Chartered Professional Engineer (in Australia and New Zealand), or European Engineer (in much of the European Union). There are international engineering agreements between relevant pressional bodies which are designed to allow engineers to practice across international borders.
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may prepare, sign and seal, and submit engineering plans and drawings to a public authority for approval, or seal engineering work for public and private clients. This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act. In other countries, no such legislation exists. In Australia, state licensing of engineers is limited to the state of Queensland. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion. In this way, these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence.[citation needed] An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.
CareersThere is no one typical career path for civil engineers. Most engineering graduates start with jobs of low responsibility, and as they prove their competence, are given more and more responsible tasks, but within each subfield of civil engineering, and even within different segments of the market within each branch, the details of a career path can vary. In some fields and in some firms, entry-level engineers are put to work primarily monitoring construction in the field, serving as the "eyes and ears" of more senior design engineers; while in other areas, entry-level engineers end up performing the more routine tasks of analysis or design and interpretation. More senior engineers can move into doing more complex analysis or design work, or management of more complex design projects, or management of other engineers, or into specialized consulting, including forensic engineering.
Engineers are in high demand at banks, financial institutions and management consultancies because of their analytical skills.
Sub-disciplinesIn general, civil engineering is concerned with the overall interface of human created fixed projects with the greater world. General civil engineers work closely with surveyors and specialized civil engineers to fit and serve fixed projects within their given site, community and terrain by designing grading, drainage, pavement, water supply, sewer service, electric and communications supply, and land divisions. General engineers spend much of their time visiting project sites, developing community consensus, and preparing construction plans. General civil engineering is also referred to as site engineering; a branch of civil engineering that primarily focuses on converting a tract of land from one usage to another. Civil engineers typically apply the principles of geotechnical engineering, structural engineering, environmental engineering, transportation engineering and construction engineering to residential, commercial, industrial and public works projects of all sizes and levels of construction
Construction engineering:
Construction engineering involves planning and execution of the designs from transportation, site development, hydraulic, environmental, structural and geotechnical engineers. As construction firms tend to have higher business risk than other types of civil engineering firms, many construction engineers tend to take on a role that is more business-like in nature: drafting and reviewing contracts, evaluating logistical operations, and closely-monitoring prices of necessary supplies
Environmental engineering:
Environmental engineering deals with the treatment of chemical, biological, and/or thermal waste, the purification of water and air, and the remediation of contaminated sites, due to prior waste disposal or accidental contamination. Among the topics covered by environmental engineering are pollutant transport, water purification, sewage treatment, and hazardous waste management. Environmental engineers can be involved with pollution reduction, green engineering, and industrial ecology. Environmental engineering also deals with the gathering of information on the environmental consequences of proposed actions and the assessment of effects of proposed actions for the purpose of assisting society and policy makers in the decision making process.
Environmental engineering is the contemporary term for sanitary engineering, though sanitary engineering traditionally had not included much of the hazardous waste management and environmental remediation work covered by the term environmental engineering. Some other terms in use are public health engineering and environmental health engineering
Geotechnical engineering:
Geotechnical engineering is an area of civil engineering concerned with the rock and soil that civil engineering systems are supported by. Knowledge from the fields of geology, material science and testing, mechanics, and hydraulics are applied by geotechnical engineers to safely and economically design foundations, retaining walls, and similar structures. Environmental concerns in relation to groundwater and waste disposal have spawned a new area of study called geoenvironmental engineering where biology and chemistry are important.
Some of the unique difficulties of geotechnical engineering are the result of the variability and properties of soil. Boundary conditions are often well defined in other branches of civil engineering, but with soil, clearly defining these conditions can be impossible. The material properties and behavior of soil are also difficult to predict due to the variability of soil and limited investigation. This contrasts with the relatively well defined material properties of steel and concrete used in other areas of civil engineering. Soil mechanics, which define the behavior of soil, is complex due to stress-dependent material properties such as volume change, stress–strain relationship, and strength
Hydraulic engineering:
Hydraulic engineering is concerned with the flow and conveyance of fluids, principally water. This area of civil engineering is intimately related to the design of pipelines, water distribution systems, drainage facilities (including bridges, dams, channels, culverts, levees, storm sewers), and canals. Hydraulic engineers design these facilities using the concepts of fluid pressure, fluid statics, fluid dynamics, and hydraulics, among others. Water resources engineering is concerned with the collection and management of water (as a natural resource). As a discipline it therefore combines hydrology, environmental science, meteorology, geology, conservation, and resource management. This area of civil engineering relates to the prediction and management of both the quality and the quantity of water in both underground (aquifers) and above ground (lakes, rivers, and streams) resources. Water resource engineers analyze and model very small to very large areas of the earth to predict the amount and content of water as it flows into, through, or out of a facility. Although the actual design of the facility may be left to other engineers.
Materials science:
Civil engineering also includes elements of materials science. Construction materials with broad applications in civil engineering include ceramics such as Portland cement concrete (PCC) and hot mix asphalt concrete, metals such as aluminum and steel, and polymers such as polymethylmethacrylate (PMMA) and carbon fibers. Current research in these areas focus around increased strength, durability, workability, and reduced cost.
Surveying:
Surveying is the process by which a surveyor measures certain dimensions that generally occur on the surface of the Earth. Modern surveying equipment, such as electronic distance measurement (EDM), total stations, GPS surveying and laser scanning, allow for accurate measurement of angular deviation, horizontal, vertical and slope distances. This information is crucial to convert the data into a graphical representation of the Earth's surface, in the form of a map. This information is then used by civil engineers, contractors and even realtors to design from, build on, and trade, respectively. Elements of a building or structure must be correctly sized and positioned in relation to each other and to site boundaries and adjacent structures. Civil engineers are trained in the basics of surveying.
Transportation engineering:
Transportation engineering is concerned with moving people and goods efficiently, safely, and in a manner conducive to a vibrant community. This involves specifying, designing, constructing, and maintaining transportation infrastructure which includes streets, canals, highways, rail systems, airports, ports, and mass transit. It includes areas such as transportation design, transportation planning, traffic engineering, urban engineering, queueing theory, pavement engineering, Intelligent Transportation System (ITS), and infrastructure management

Engineering drawing

2008-01-08T03:26:00.000-08:00

Engineering drawing introduction:
An engineering drawing is a type of drawing that is technical in nature, used to fully and clearly define requirements for engineered items, and is usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance (such as typefaces and line styles), size, etc. Its purpose is to accurately and unambiguously capture all the geometric features of a product or a component. The end goal of an engineering drawing is to convey all the required information that will allow a manufacturer to produce that component.
Engineering drawings are often referred to as "blueprints" or "bluelines". However, the terms are rapidly becoming an anachronism, since most copies of engineering drawings that were formerly made using a chemical-printing process that yielded graphics on blue-colored paper or, alternatively, of blue-lines on white paper, have been superseded by more modern reproduction processes that yield black or multicolour lines on white paper.
The process of producing engineering drawings, and the skill of producing them, is often referred to as technical drawing, although technical drawings are also required for disciplines that would not ordinarily be thought of as parts of engineering

Common features of engineering drawings:
Drawings convey the following critical information:
Geometry – the shape of the object; represented as views; how the object will look when it is viewed from various standard directions, such as front, top, side, etc. Dimensions – the size of the object is captured in accepted units. Tolerances – the allowable variations for each dimension. Material – represents what the item is made of. Finish – specifies the surface quality of the item, functional or cosmetic. For example, a mass-marketed product usually requires a much higher surface quality than, say, a component that goes inside industrial machinery. A variety of line styles graphically represent physical objects. Types of lines include the following:
visible – are continuous lines used to depict edges directly visible from a particular angle. hidden – are short-dashed lines that may be used to represent edges that are not directly visible. center – are alternately long- and short-dashed lines that may be used to represent the axes of circular features. cutting plane – are thin, medium-dashed lines, or thick alternately long- and double short-dashed that may be used to define sections for section views. section – are thin lines in a pattern (pattern determined by the material being "cut" or "sectioned") used to indicate surfaces in section views resulting from "cutting." Section lines are commonly referred to as "cross-hatching." Lines can also be classified by a letter classification in which each line is given a letter.
*)Type A lines show the outline of the feature of an object. They are the thickest lines on a drawing and done with a pencil softer than HB.
*)Type B lines are dimension lines and are used for dimensioning, projecting, extending, or leaders. A harder pencil should be used, such as a 2H.
*)Type C lines are used for breaks when the whole object is not shown. They are freehand drawn and only for short breaks. 2H pencil
*)Type D lines are similar to Type C, except they are zigzagged and only for longer breaks. 2H pencil
*)Type E lines indicate hidden outlines of internal features of an object. They are dotted lines. 2H pencil
*)Type F lines are Type F[typo] lines, except they are used for drawings in electrotechnology. 2H pencil
*)Type G lines are used for centre lines. They are dotted lines, but a long line of 10–20mm, then a gap, then a small line of 2mm. 2H pencil
*)Type H lines are the same as Type G, except that every second long line is thicker. They indicate the cutting plane of an object. 2H pencil
*)Type K lines indicate the alternate positions of an object and the line taken by that object. They are drawn with a long line of 10–20mm, then a small gap, then a small line of 2mm, then a gap, then another small line. 2H pencil.
*)The ISO standard considers a projection on the opposite direction, like an X-ray radiography; the top view is under the front view, the right view is at the left of the front view... This is called First Angle Projection.
*)The American standard (called Third Angle Projection) places the left view on the left and the top view on the top.

Assembly modelling

2008-01-08T03:25:00.000-08:00

Assembly modelling:
Assembly Modelling is technology and methods used by Computer-aided design and Product visualization computer software systems to handle multiple files that represent components within a product. The components within an assembly are represented as solid or surface models
The designer generally has access to models that others are working on concurrently. For example, several people may be designing one machine that has many parts. New parts are added to an assembly model as they are created. Each designer has access to the assembly model, while a work in progress, and while working in their own parts. The design evolution is visible to everyone involved.
The individual data files describing the 3D geometry of individual components are assembled together through a number of sub-assembly levels to create an assembly describing the whole product. All CAD and CPD systems support this form of bottom-up construction. Some systems, via associative copying of geometry between components also allow top-down method of design.
Components can be positioned within the product assembly using absolute coordinate placement methods or by means of mating conditions. Mating conditions are definitions of the relative position of components between each other; for example alignment of axis of two holes or distance of two faces from one another. The final position of al components based on these relationships is calculated using a geometry constraint engine built into the CAD or visualization package.
The importance of Assemly Modelling in achieving the full benefits of PLM has led to ongoing advances in this technology. These include the use of lightweight data structures such as JT that allow visualization of and interaction with large amounts of product data, direct interface to between Digital Mockups and PDM systems and active digital mockup technology that unites the ability to visualize the assembly mockup with the ability to measure, analyze, simulate, design and redesign

Freeform surface modelling

2008-01-08T03:12:00.000-08:00

Freeform surface modelling:

Introduction:

The technology encompasses two main fields. Either creating aesthetic (Class A surfaces) that also perform a function; for example, car bodies and consumer product outer forms, or technical surfaces for components such as gas turbine blades and other fluid dynamic engineering components.CAD software packages use two basic methods for the creation of surfaces. The first begins with construction curves (splines) from which the 3D surface is then swept (section along guide rail) or meshed (lofted) through.

Surfaces:

Freeform surface, or freeform surfacing, is used in CAD and other computer graphics software to describe the skin of a 3D geometric element. Freeform surfaces do not have rigid radial dimensions, unlike regular surfaces such as planes, cylinders and conic surfaces. They are used to describe forms such as turbine blades, car bodies and boat hulls. Initially developed for the automotive and aerospace industries, freeform surfacing is now widely used in all engineering design disciplines from consumer goods products to ships. Most systems today use nonuniform rational B-spline (NURBS) mathematics to describe the surface forms; however, there are other methods such as Gorden surfaces or Coon surfaces .The forms of freeform surfaces (and curves) are not stored or defined in CAD software in terms of polynomial equations, but by their poles, degree, and number of patches (segments with spline curves). The degree of a surface determines its mathematical properties, and can be seen as representing the shape by a polynomial with variables to the power of the degree value. For example, a surface with a degree of 1 would be a flat cross section surface. A surface with degree 2 would be curved in one direction, while a degree 3 surface could (but does not necessarily) change once from concave to convex curvature. Some CAD systems use the term order instead of degree. The order of a polynomial is one greater than the degree, and gives the number of coefficients rather than the greatest exponent.The poles (sometimes known as control points) of a surface define its shape. The natural surface edges are defined by the positions of the first and last poles. (Note that a surface can have trimmed boundaries.) The intermediate poles act like magnets drawing the surface in their direction. The surface does not, however, go through these points. The second and third poles as well as defining shape, respectively determine the start and tangent angles and the curvature. In a single patch surface (Bézier surface), there is one more pole than the degree values of the surface. Surface patches can be merged into a single NURBS surface; at these points are knot lines. The number of knots will determine the influence of the poles on either side and how smooth the transition is. The smoothness between patches, known as continuity, is often referred to in terms of a C value:
C0: just touching, could have a nick C1: tangent, but could have sudden change in curvature C2: the patches are curvature continuous to one another Two more important aspects are the U and V parameters. These are values on the surface ranging from 0 to 1, used in the mathematical definition of the surface and for defining paths on the surface: for example, a trimmed boundary edge. Note that they are not proportionally spaced along the surface. A curve of constant U or constant V is known as an isoperimetric curve, or U (V) line. In CAD systems, surfaces are often displayed with their poles of constant U or constant V values connected together by lines; these are known as control polygons

Modelling:

When defining a form, an important factor is the continuity between surfaces - how smoothly they connect to one another.One example of where surfacing excels is automotive body panels. If two curved areas of the panel have different radii of curvature and are blended together, maintaining tangential continuity (meaning that the blended surface doesn't change direction suddenly, but smoothly) won't be enough. They need to have a continuous rate of curvature change between the two sections, or else their reflections will appear disconnected.
The continuity is defined using the terms
G0 – position (touching) G1 – tangent (angle) G2 – curvature (radius) G3 – acceleration (rate of change of curvature) To achieve a high quality NURBS or Bezier surface, degrees of 5 or greater are generally used. Depending on the product and production process, different levels of accuracy are used but tolerances usually range from 0.02 mm to .001 mm (for example, in fairing of BIW concept surfaces to production surface). Obviously for ship building this need not be so tight and for precision gears and medical devices it is much finer.

Solid Modelling

2008-01-08T03:08:00.000-08:00

Solid modeling:
Solid modeling (or modelling) is the unambiguous representation of the solid parts of an object, that is, models of solid objects suitable for computer processing. It is also known as volume modeling. Other modeling methods include surface models (used extensively in automotive and consumer product design as well as entertainment animation) and wire frame models (which can be ambiguous about solid volume).Primary uses of solid modeling are for CAD, engineering analysis, computer graphics and animation, rapid prototyping, medical testing, product visualization and visualization of scientific research

Basic theoretical concepts:
It has been suggested that Parametric feature based modeler be merged into this article or section. (Discuss) It has been suggested that Change state be merged into this article or section. (Discuss) It has been suggested that Transmigration operation be merged into this article or section. (Discuss) It has been suggested that Euler boolean operation be merged into this article or section. (Discuss) There are several ways by which a solid model may be constructed, usually from simpler objects (such as surfaces, lines, and/or points).
Sweeping:
An area feature is "swept out" by moving a primitive along a path to form a solid feature. These volumes either add to the object ("extrusion") or remove material ("cutter path"). Also known as 'sketch based modeling'. Analogous to various manufacturing techniques such as extrusion, milling, lathe and others.
Boundary representation (BRep) :
A solid object is represented by boundary surfaces and then filled to make solid. Also knowing as 'surfacing'. Analogous to various manufacturing techniques; Injection moulding, casting, forging, thermoforming, etc. Parameterized primitive instancing: An object is specified by reference to a library of parameterized primitives. For example, a bolt is modeled for a library, this model is used for all bolt sizes by modifying a set of its parameters.
Spatial occupancy enumeration (voxel) :
The whole space is subdivided into regular cells, and the object is specified by the set of cells it occupies. Models described this way lend themselves to Finite difference analysis. This is usually done after a model is made, as part of automated pre-processing for analysis software.
Cellular decomposition :Similar to "spatial occupancy", but the cells are neither regular, nor "prefabricated". Models described this way lend themselves to FEA. This is usually done after a model is made, as part of automated pre-processing for analysis software.
Constructive solid geometry (CSG) :
Simple objects (primitives) are combined using Boolean operations (union, difference, intersection) and linear transformations. A special data structure is called a CSG-tree, where primitives are leaves and operations are nodes. Function representation (FRep) :Any object is represented by a single real function of point coordinates. A point is outside the object if the function is negative, inside the object if the function is positive, and on the boundary if the function is zero (isosurface). The function is evaluated at a point by traversing a tree structure similar to the CSG-tree.
Feature based modeling :
Complex combinations of objects and operators are considered together as a unit which can be modified or duplicated. Order of operations is kept in a history tree, and parametric changes can propagate through the tree.
Parametric modeling :
Attributes of features are parameterized, giving them labels rather than only giving them fixed numeric dimensions, and relationships between parameters in the entire model are tracked, to make changing numeric values of parameters easier. Almost always combined with features, giving parametric feature based modeling.
Facet modeling :
Forming the outside surface form of the volume from any triangular planes Often used in reverse engineering of physical models

History:
Solid modeling has to be seen in context of the whole history of CAD, the key milestones being the development of Romulus which went on to influence the development of Parasolid and ACIS and thus the mid-range Windows based feature modelers such as IronCAD, Alibre Design, SolidWorks, and Solid Edge and the arrival of parametric solid models system like T-Flex and Pro/ENGINEER

capabilities of modern CAD systems

2008-01-01T03:12:00.000-08:00

The capabilities of modern CAD systems include:

* Wireframe geometry creation
* 3D parametric feature based modelling, Solid modelling
* Freeform surface modelling
* Automated design of assemblies, which are collections of parts and/or other assemblies
* create Engineering drawings from the solid models
* Reuse of design components
* Ease of modification of design of model and the production of multiple versions
* Automatic generation of standard components of the design
* Validation/verification of designs against specifications and design rules
* Simulation of designs without building a physical prototype
* Output of engineering documentation, such as manufacturing drawings, and Bills of Materials to reflect the BOM required to build the product
* Import/Export routines to exchange data with other software packages
* Output of design data directly to manufacturing facilities
* Output directly to a Rapid Prototyping or Rapid Manufacture Machine for industrial prototypes
* maintain libraries of parts and assemblies
* calculate mass properties of parts and assemblies
* aid visualization with shading, rotating, hidden line removal, etc...
* Bi-directional parametric association (modification of any feature is reflected in all information relying on that feature; drawings, mass properties, assemblies, etc... and counter wise)
* kinematics, interference and clearance checking of assemblies
* sheet metal
* hose/cable routing
* electrical component packaging
* inclusion of programming code in a model to control and relate desired attributes of the model
* Programmable design studies and optimization
* Sophisticated visual analysis routines, for draft, curvature, curvature continuity...

wire frames

2008-01-01T03:08:00.000-08:00

Wire frame model: A wire frame model is a visual presentation of an electronic representation of a three dimensional or physical object used in 3D computer graphics. It is created by specifying each edge of the physical object where two mathematically continuous smooth surfaces meet, or by connecting an object's constituent vertices using straight lines or curves. The object is projected onto the computer screen by drawing lines at the location of each edge.
Sample rendering of a wireframe cube, icosahedron, and approximate sphere
Sample rendering of a wireframe cube, icosahedron, and approximate sphere

Using a wire frame model allows visualization of the underlying design structure of a 3D model. Traditional 2-dimensional views and drawings can be created by appropriate rotation of the object and selection of hidden line removal via cutting planes.

Since wire frame renderings are relatively simple and fast to calculate, they are often used in cases where a high screen frame rate is needed (for instance, when working with a particularly complex 3D model, or in real-time systems that model exterior phenomena). When greater graphical detail is desired, surface textures can be added automatically after completion of the initial rendering of the wire frame. This allows the designer to quickly review changes or rotate the object to new desired views without long delays associated with more realistic rendering.

The wire frame format is also well suited and widely used in programming tool paths for DNC (Direct Numerical Control) machine tools.

Effects

2008-01-01T02:24:00.000-08:00

The Effects of CAD:

Starting in the late 1980s, the development of readily affordable CAD programs that could be run on personal computers began a trend of massive downsizing in drafting departments in many small to mid-size companies. As a general rule, one CAD operator could readily replace at least three or five drafters using traditional methods. Additionally, many engineers began to do their own drafting work, further eliminating the need for traditional drafting departments. This trend mirrored that of the elimination of many office jobs traditionally performed by a secretary as word processors, spread sheets, data bases , etc. became standard software packages that "everyone" was expected to learn.

Another consequence had been that since the latest advances were often quite expensive, small and even mid-size firms often could not compete against large firms who could use their computational edge for competitive purposes. Today, however, hardware and software costs have come down. Even high-end packages work on less expensive platforms and some even support multiple platforms. The costs associated with CAD implementation now are more heavily weighted to the costs of training in the use of these high level tools, the cost of integrating a CAD/CAM/CAE PLM using enterprise across multi-CAD and multi-platform environments and the costs of modifying design workflows to exploit the full advantage of CAD tools. CAD vendors have been effective in providing tools to lower these costs.

The adoption of CAD studio or "paper-less studio," as it is sometimes called, in architectural schools was not without resistance, however. Teachers were worried that sketching on a computer screen did not replicate the skills associated with age-old practice of sketching in a sketchbook. Furthermore, many teachers were worried that students would be hired for their computer skills rather than their design skill, as was indeed common in the 1990s. Today, however, (for better or worse, depending on the authority cited) education in CAD is now accepted across the board in schools of architecture. It should be noted, however, that not all architects have wanted to join the CAD revolution.

uses of CAD

2008-01-01T02:23:00.000-08:00

Using CAD:

CAD is one of the many tools used by engineers and designers and is used in many ways depending on the profession of the user and the type of software in question. Each of the different types of CAD systems requires the operator to think differently about how he will use them and he must design their virtual components in a different manner for each.

There are many producers of the lower-end 2D systems, including a number of free and open source programs. These provide an approach to the drawing process without all the fuss over scale and placement on the drawing sheet that accompanied hand drafting, since these can be adjusted as required during the creation of the final draft.

3D wireframe is basically an extension of 2D drafting. Each line has to be manually inserted into the drawing. The final product has no mass properties associated with it and cannot have features directly added to it, such as holes. The operator approaches these in a similar fashion to the 2D systems, although many 3D systems allow using the wireframe model to make the final engineering drawing views.

3D "dumb" solids (programs incorporating this technology include AutoCAD and Cadkey 19) are created in a similar fashion to the way you would create the real world object. Each object and feature, after creation, is what it is. If the operator wants to change it, he must add "material" to it, subtract "material" from it, or delete the object or feature and start over. Due to this, it doesn't matter how the initial operator creates his components, as long as the final product is represented correctly. If future modifications are to be made, the method used to make the original part will not, in most cases, affect the procedure used to make the new modifications. Draft views can easily be generated from the models. Assemblies generally don't include tools to easily allow motion of components, set limits to their motion, or identify interference between components.

3D parametric solid modeling (programs incorporating this technology include Alibre Design, TopSolid, SolidWorks, and Solid Edge) require the operator to use what is referred to as "design intent". The objects and features created are adjustable. Any future modifications will be simple, difficult, or nearly impossible, depending on how the original part was created. One must think of this as being a "perfect world" representation of the component. If a feature was intended to be located from the center of the part, the operator needs to locate it from the center of the model, not, perhaps, from a more convenient edge or an arbitrary point, as he could when using "dumb" solids. Parametric solids require the operator to consider the consequences of his actions carefully. What may be simplest today could be worst case tomorrow.

Some software packages provide the ability to edit parametric and non-parametric geometry without the need to understand or undo the design intent history of the geometry by use of direct modeling functionality.

Draft views are able to be generated easily from the models. Assemblies usually incorporate tools to represent the motions of components, set their limits, and identify interference. The tool kits available for these systems are ever increasing, including 3D piping and injection mold designing packages.

Mid range software was integrating parametric solids more easily to the end user: integrating more intuitive functions (SketchUp), going to the best of both worlds with 3D dumb solids with parametric characteristics (VectorWorks) or making very real-view scenes in relative few steps (Cinema4D).

Top end systems offer the capabilities to incorporate more organic, aesthetics and ergonomic features into designs. Freeform surface modelling is often combined with solids to allow the designer to create products that fit the human form and visual requirements as well as they interface with the machine.

The CAD operator's ultimate goal should be to make future work on the current project as simple as possible. This requires a solid understanding of the system being used. A little extra time spent now could mean a great savings later.

CAD introduction

2007-12-17T10:25:00.001-08:00

Computer-aided design (CAD) is the use of computer technology to aid in the design of a product. computer packages range from 2D vector base drafting systems to 3D solid and surface modellers.

Origins and terminology

CAD originally meant Computer-Aided Drafting because of its original use as a replacement for traditional drafting. Now, CAD usually means Computer Aided Design to reflect the fact that modern CAD tools do more than just drafting.
CAD is sometimes translated as "computer-assisted", "computer-aided drafting", or a similar phrase. Related acronyms are CADD, which stands for "computer-aided design and drafting",
CAID for computer-aided industrial design and CAAD, for " Computer-aided Architectural Design". All these terms are essentially synonymous, but there are a few subtle differences in meaning and application. CAM(Computer-aided manufacturing) is also often used in a similar way, or as a combination (CAD/CAM). The term CAD is generally used for graphical design, whereas non-graphical computer-aided design, though there may be a focus on shape and shape-related functions, is usually called knowledge Based Engineering(KBE).

Introduction

CAD is used to design, develop and optimize products, which can be goods used by end consumers or intermediate goods used in other products. CAD is also extensively used in the design of tools and machinery used in the manufacture of components, and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories).

CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.

The CAD process ;Commercial floor plan

CAD has become an especially important technology, within the scope of Computer aided technologies, with benefits such as lower product development costs and a greatly shortened design cycle. CAD enables designers to lay out and develop work on screen, print it out and save it for future editing, saving time on their drawings.

History of CAD

2007-12-17T10:22:00.000-08:00

History

Designers have long used computers for their calculations. Initial developments were carried out in the 1960s within the aircraft and automotive industries in the area of 3D surface construction and NC programming, most of it independent of one another and often not publicly published until much later. Some of the mathematical description work on curves was developed in the early 1940s by Isaac Jacob Schoenberg, Apalatequi (Douglas Aircraft) and Roy Liming (North American Aircraft). Robert A. Heinlein in his 1957 novel The Door into Summer suggested the possibility of a robotic Drafting Dan. However, probably the most important work on polynomial curves and sculptured surface was done by Pierre Bezier (Renault), Paul de Casteljau (Citroen), Steven Anson Coons (MIT, Ford), James Ferguson (Boeing), Carl de Boor (GM), Birkhoff (GM) and Garibedian (GM) in the 1960s and W. Gordon (GM) and R. Riesenfeld in the 1970s.

It is argued that a turning point was the development of SKETCHPAD system in MIT in 1963 by Ivan Sutherland (who later created a graphics technology company with Dr. David Evans). The distinctive feature of SKETCHPAD was that it allowed the designer to interact with his computer graphically: the design can be fed into the computer by drawing on a CRT Monitor with a light pen. Effectively, it was a prototype of graphical user interface, an indispensable feature of modern CAD.

First commercial applications of CAD were in large companies in the automotive and aerospace industries, as well as in electronics. Only large corporations could afford the computers capable of performing the calculations. Notable company projects were at GM (Dr. Patrick J.Hanratty) with DAC-1 (Design Augmented by Computer) 1964; Lockheed projects; Bell GRAPHIC 1 and at Renault (Bezier) – UNISURF 1971 car body design and tooling.

One of the most influential events in the development of CAD was the founding of MCS (Manufacturing and Consulting Services Inc.) in 1971 by Dr. P. J. Hanratty, who wrote the system ADAM (Automated Drafting And Machining) but more importantly supplied code to companies such as McDonnell Douglas (Unigraphics), Computervision (CADDS), Calma, Gerber, Autotrol and Control Data.

As computers became more affordable, the application areas have gradually expanded. The development of CAD software for personal desk-top computers was the impetus for almost universal application in all areas of construction.

Other key points in the 1960s and 1970s would be the foundation of CAD systems United Computing, Intergraph, IBM, Intergraph IGDS in 1974 (which led to Bentley MicroStation in 1984)

CAD implementations have evolved dramatically since then. Initially, with 2D in the 1970s, it was typically limited to producing drawings similar to hand-drafted drawings. Advances in programming and computer hardware, notably solid modeling in the 1980s, have allowed more versatile applications of computers in design activities.

Key products for 1981 were the solid modelling packages -Romulus (ShapeData) and Uni-Solid (Unigraphics) based on PADL-2 and the release of the surface modeler CATIA (Dassault Systemes). Autodesk was founded 1982 by John Walker, which led to the 2D system AutoCAD. The next milestone was the release of Pro/Engineer in 1988, which heralded greater usage of feature-based modeling methods and parametric linking of the parameters of features. Also of importance to the development of CAD was the development of the B-rep solid modeling kernels (engines for manipulating geometrically and topologically consistent 3D objects) Parasoli (ShapeData) and ACIS (Spatial Technology Inc.) at the end of the 1980s and beginning of the 1990s, both inspired by the work of Ian Braid. This led to the release of mid-range packages such as SolidWorks in 1995, SolidEdge (Intergraph) in 1996, and IronCAD in 1998. Today CAD is one of the main tools used in designing products.

system technologies

2007-12-15T23:21:00.001-08:00

Hardware and OS technologies
Today most CAD computer workstations are Windows based PCs; some CAD systems also run on hardware running with one of the Unix operating systems and a few with Linux. Some CAD systems such as QCad or NX provide multiplatform support including Windows, Linux, UNIX and Mac OSX.
Generally no special hardware is required with the exception of a high end OpenGL based Graphics card; however for complex product design, machines with high speed (and possibly multiple) CPUs and large amounts of RAM are recommended. The human-machine interface is generally via a computer mouse but can also be via a pen and digitizing graphics tablet. Manipulation of the view of the model on the screen is also sometimes done with the use of a spacemouse/SpaceBall. Some systems also support stereoscopic glasses for viewing the 3D model.
CAD is one of the many tools used by engineers and designers and is used in many ways depending on the profession of the user and the type of software in question. Each of the different types of CAD systems requires the operator to think differently about how he will use them and he must design their virtual components in a different manner for each.
There are many producers of the lower-end 2D systems, including a number of free and open source programs. These provide an approach to the drawing process without all the fuss over scale and placement on the drawing sheet that accompanied hand drafting, since these can be adjusted as required during the creation of the final draft.
3D wireframe is basically an extension of 2D drafting. Each line has to be manually inserted into the drawing. The final product has no mass properties associated with it and cannot have features directly added to it, such as holes. The operator approaches these in a similar fashion to the 2D systems, although many 3D systems allow using the wireframe model to make the final engineering drawing views.
3D "dumb" solids (programs incorporating this technology include AutoCAD and Cadkey 19) are created in a similar fashion to the way you would create the real world object. Each object and feature, after creation, is what it is. If the operator wants to change it, he must add "material" to it, subtract "material" from it, or delete the object or feature and start over. Due to this, it doesn't matter how the initial operator creates his components, as long as the final product is represented correctly. If future modifications are to be made, the method used to make the original part will not, in most cases, affect the procedure used to make the new modifications. Draft views can easily be generated from the models. Assemblies generally don't include tools to easily allow motion of components, set limits to their motion, or identify interference between components.
3D parametric solid modeling (programs incorporating this technology include Alibre Design, TopSolid, SolidWorks, and Solid Edge) require the operator to use what is referred to as "design intent". The objects and features created are adjustable. Any future modifications will be simple, difficult, or nearly impossible, depending on how the original part was created. One must think of this as being a "perfect world" representation of the component. If a feature was intended to be located from the center of the part, the operator needs to locate it from the center of the model, not, perhaps, from a more convenient edge or an arbitrary point, as he could when using "dumb" solids. Parametric solids require the operator to consider the consequences of his actions carefully. What may be simplest today could be worst case tomorrow.
Some software packages provide the ability to edit parametric and non-parametric geometry without the need to understand or undo the design intent history of the geometry by use of direct modeling functionality.
Draft views are able to be generated easily from the models. Assemblies usually incorporate tools to represent the motions of components, set their limits, and identify interference. The tool kits available for these systems are ever increasing, including 3D piping and injection mold designing packages.
Mid range software was integrating parametric solids more easily to the end user: integrating more intuitive functions (SketchUp), going to the best of both worlds with 3D dumb solids with parametric characteristics (VectorWorks) or making very real-view scenes in relative few steps (Cinema4D).
Top end systems offer the capabilities to incorporate more organic, aesthetics and ergonomic features into designs. Freeform surface modelling is often combined with solids to allow the designer to create products that fit the human form and visual requirements as well as they interface with the machine.
The CAD operator's ultimate goal should be to make future work on the current project as simple as possible. This requires a solid understanding of the system being used. A little extra time spent now could mean a great savings later.