2. Computer-aided design Computer-aided design (CAD), also known as computer- aided drafting and design (CADD), is the use of computer technology for the process of design and design- documentation. Computer Aided Design describes the way in which technology is folded into a design process. Computer Aided Drafting describes the process of drafting with a computer. CADD output is often in the form of electronic files for print or machining operations. The output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions. CAD may be used to design curves and figures in two- dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) objects. CAD is also widely used to produce computer animation for special effects in movies, advertising and technical manuals.

3. Overview Modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle, even from the inside looking out. Some CAD software is capable of dynamic mathematic modeling, in which case it may be marketed as CADD — computer-aided design and drafting. CAD is used in the design of tools and machinery 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). It can also be used to design objects. CAD has become an especially important technology within the scope of computer-aided technologies 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

4. Uses Computer-aided design 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. CAD is one part of the whole Digital Product Development (DPD) activity within the Product Lifecycle Management (PLM) process, and as such is used together with other tools, which are either integrated modules or stand-alone products, such as: 1.Computer-aided engineering (CAE) and Finite element analysis (FEA) 1.Computer-aided engineering (CAE) and Finite element analysis (FEA) 2.Computer-aided manufacturing (CAM) including instructions to Computer Numerical Control (CNC) machines 2.Computer-aided manufacturing (CAM) including instructions to Computer Numerical Control (CNC) machines 3.Photo realistic rendering 3.Photo realistic rendering 4.Document management and revision control using Product Data Management (PDM). 4.Document management and revision control using Product Data Management (PDM). Potential blockage of view corridors and shadow studies are also frequently analyzed through the use of CAD.

5. Capabilities There are several different types of CAD. Each of these different types of CAD systems require the operator to think differently about how we will use them and we must design their virtual components in a different manner for each. The capabilities of modern CAD systems include: 1.Wireframe geometry creation 1.Wireframe geometry creation 2.3D parametric feature based modelling, Solid modelling 2.3D parametric feature based modelling, Solid modelling 3.Freeform surface modelling 3.Freeform surface modelling 4.Automated design of assemblies, which are collections of parts and/or other assemblies 4.Automated design of assemblies, which are collections of parts and/or other assemblies 5.Create Engineering drawings from the solid models 5.Create Engineering drawings from the solid models 6.Reuse of design components 6.Reuse of design components 7.Maintain libraries of parts and assemblies. 7.Maintain libraries of parts and assemblies.

6. Fields of use Fashion Design Fashion Design AEC Architecture Engineering and Construction AEC Architecture Engineering and Construction MCAD Mechanical MCAD Mechanical1.Automotive2.Aerospace 3.Consumer Goods 4.Machinery 5.Ship Building Manufacturing process planning Manufacturing process planning Coordinator Coordinator Face Mapping Face Mapping Survey Draughting Survey Draughting SSMON, Stability Monitoring database SSMON, Stability Monitoring database Generalized co-ordinate and database connectivity Generalized co-ordinate and database connectivity DBDS Drill and Blast database system DBDS Drill and Blast database system

7. Software providers today There are many CAD software products currently on the market. More than half of the market is however covered by the four main PLM corporations Autodesk, Dassault Systems, PTC, and UGS Corp., but there are many other CAD packages with smaller user bases or covering niche user areas. Packages can be classified into 3 types: Packages can be classified into 3 types: 1.2D drafting systems (e.g. AutoCAD, Microstation) 1.2D drafting systems (e.g. AutoCAD, Microstation) 2. Mid-range 3D solid feature modellers (e.g. SolidWorks, SolidEdge, Alibre) 2. Mid-range 3D solid feature modellers (e.g. SolidWorks, SolidEdge, Alibre) 3.High-end 3D hybrid systems (e.g. CATIA, NX (Unigraphics)) 3.High-end 3D hybrid systems (e.g. CATIA, NX (Unigraphics))

8. Software Technologies Originally software for CAD systems were developed with computer language such as Fortran, but with the advancement of Object-oriented programming methods this has over the last decade or so radically changed. The development of a typical modern Parametric feature based modeler and freeform surface systems are built around a number of key, C programming language, modules with their own APIs. A CAD system can be seen as built up from the interaction a GUI with an Associative engine and Geometry constraint engine controlling BREP, CSG and NURBS geometry via a Geometric modeling kernel.

9. Hardware and OS technologies Today, CAD systems exist for all the major platforms (Windows, Linux, UNIX and Mac OS X); some packages even support multiple platforms. No special hardware is required for most CAD software. However, some CAD systems can do graphically and computationally expensive tasks, so good graphics card, 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.

10. Features of CAD Computer-aided design (CAD) involves creating computer models defined by geometrical parameters. These models typically appear on a computer monitor as a three-dimensional representation of a part or a system of parts, which can be readily altered by changing relevant parameters. CAD systems enable designers to view objects under a wide variety of representations and to test these objects by simulating real-world conditions CAD systems enable designers to view objects under a wide variety of representations and to test these objects by simulating real-world conditions

11. Why we go for CAD services Increased productivity Increased productivity Less errors using 3D Modeling Less errors using 3D Modeling Improved collaboration Improved collaboration Quicker Turn-around time Quicker Turn-around time Lower overhead costs Lower overhead costs

12. Effects of CAD Today,hardware and software costs have come down. Even high-end packages work on less expensive platforms and some even support multiple platforms. There are three categories. 1.Improved and simplified user interfaces. This includes the availability of “role” specific tailorable user interfaces through which commands are presented to users in a form appropriate to their function and expertise. 1.Improved and simplified user interfaces. This includes the availability of “role” specific tailorable user interfaces through which commands are presented to users in a form appropriate to their function and expertise. 2.Enhancements to application software. One such example is improved design-in-context, through the ability to model/edit a design component from within the context of a large, even multi-CAD, active digital mockup. 2.Enhancements to application software. One such example is improved design-in-context, through the ability to model/edit a design component from within the context of a large, even multi-CAD, active digital mockup. 3.User oriented modeling options. This includes the ability to free the user from the need to understand the design intent history of a complex intelligent model. 3.User oriented modeling options. This includes the ability to free the user from the need to understand the design intent history of a complex intelligent model.

13. Advantages of CAD Can be easily erased and changed Can be easily erased and changed Can be zoomed in for more detailed sections Can be zoomed in for more detailed sections Can be copied and pasted many times Can be copied and pasted many times Depending on skill, can be neater Depending on skill, can be neater Can be quicker Can be quicker Can be sent to elsewhere quickly Can be sent to elsewhere quickly Can be stored in a safe place Can be stored in a safe place Can be checked for measurements by the computer Can be checked for measurements by the computer

14. Disadvantages of CAD If computer problem, all data will be lost If not checked properly, the object created can go very wrong Can be very expensive Can be hard to do and handling needs training Since not manual, can be slightly irritating because if not familiar with technology, it is very hard to insure exactly what is wanted by the designer. Ex: If wanted something engraved instead of cut, the line colour has to be changed into black instead of red.

15. Compare with 2D CAD A few advantages of 2D CAD: 1.Reduced design timescales. 2.Reuse of designs. 3.Drawing errors can be corrected easily. 4.Drawings can be sent/received via email in seconds. Disadvantages: 1.Time & cost of implementing the CAD system 2.Time & cost of training people to use the CAD. 3.Time & cost of migrating legacy drawings into CAD format

16. Compare with 3D CAD Advantages of 3D CAD: 1.More stylish /complex products can be designed using 3D surfacing. 2.Parametric modelling allows many design iterations to be generated & evaluated quickly. 3.Designs can be analyzed and optimized virtually using finite element analysis. 4.Clearance/interference checks can be mase easily 5.3D CAD data can be imported directly in to CAM software, further reducing timescales and mistakes from interpretation of 2D drawings

17. Conclusion Computer-aided design (CAD) is the use of a wide range of computer-based tools that assist engineers, architects and other design professionals in their design activities. CAD is also extensively used in the design of tools and machinery used in the manufacture of components. CAD is used throughout the engineering process from conceptual design and layout, through detailed engineering and analysis of components to definition of manufacturing methods.