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Computer-aided design (CAD) is the use of
computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as Computer program, programs. These ...

computer
s (or ) to aid in the creation, modification, analysis, or optimization of a
design A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process, or the result of that plan or specification in the form of a prototype A prototype is an early sample, mode ...

design
. This software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. Designs made through CAD software are helpful in protecting products and inventions when used in
patent A patent is a type of intellectual property Intellectual property (IP) is a category of property Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depe ...

patent
applications. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD (for c''omputer aided design and drafting'') is also used. Its use in designing electronic systems is known as
electronic design automation Electronic design automation (EDA), also referred to as electronic computer-aided design (ECAD), is a category of software tools A programming tool or software development tool is a that s use to create, debug, maintain, or otherwise support ...
(EDA). In
mechanical design Mechanical engineering is an engineering branch that combines engineering physics and engineering mathematics, mathematics principles with materials science to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldes ...
it is known as mechanical design automation (MDA) or computer-aided drafting (CAD), which includes the process of creating a
technical drawing Technical drawing, drafting or drawing, is the act and discipline Discipline is action ACTION is a bus operator in Canberra Canberra ( ) is the capital city of Australia. Founded following the Federation of Australia, federat ...

technical drawing
with the use of
computer software Software is a collection of instructions Instruction or instructions may refer to: Computing * Instruction, one operation of a processor within a computer architecture instruction set * Computer program, a collection of instructions Music * I ...

computer software
. CAD software for mechanical design uses either vector-based graphics to depict the objects of traditional drafting, or may also produce
raster graphics upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...
showing the overall appearance of designed objects. However, it involves more than just shapes. As in the manual
drafting Drafting or draughting may refer to: * Campdrafting, an Australian equestrian sport * Drafting (aerodynamics), slipstreaming * Drafting (writing), writing something that is likely to be amended * Technical drawing, the act and discipline of compos ...
of
technical Technical may refer to: * Technical (vehicle), an improvised fighting vehicle * Technical analysis, a discipline for forecasting the future direction of prices through the study of past market data * Technical drawing, showing how something is con ...

technical
and
engineering drawing An engineering drawing is a type of technical drawing Technical drawing, drafting or drawing, is the act and discipline Discipline is action ACTION is a bus operator in Canberra Canberra ( ) is the capital city of Austra ...
s, the output of CAD must convey information, such as
material Material is a substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or owner of attributes * Chemical substance, a material with a definite chemical composition * Matter, anything that has mass and ...

material
s,
process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process A business process, business method ...

process
es,
dimension In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular s ...

dimension
s, and tolerances, according to application-specific conventions. CAD may be used to design curves and figures in
two-dimensional 300px, Bi-dimensional Cartesian coordinate system Two-dimensional space (also known as 2D space, 2-space, or bi-dimensional space) is a geometric setting in which two values (called parameter A parameter (), generally, is any characteristic ...
(2D) space; or curves, surfaces, and solids in
three-dimensional Three-dimensional space (also: 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called parameter A parameter (from the Ancient Greek language, Ancient Greek wikt:παρά#Ancient Greek, παρά, ''par ...
(3D) space. CAD is an important industrial art extensively used in many applications, including
automotive
automotive
,
shipbuilding Shipbuilding is the construction Construction is a general term meaning the and to form , , or ,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and c ...

shipbuilding
, and
aerospace Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications. Aerospace engineering consists of aeronautics and astronau ...

aerospace
industries, industrial and
architectural design Building design refers to the broadly based architecture, architectural, Architectural engineering, engineering and Technology, technical applications to the design of buildings. All building projects require the services of a building designer, t ...
,
prosthetics In medicine Medicine is the Art (skill), art, science, and Praxis (process) , practice of caring for a patient and managing the diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment or Palliative care , palliation of t ...
, and many more. CAD is also widely used to produce
computer animation Computer animation is the process used for digitally generating animated images. The more general term computer-generated imagery Computer-generated imagery (CGI) is the application of computer graphics Computer graphics deals with gen ...
for
special effect Special effects (often abbreviated as SFX, SPFX, F/X or simply FX) are illusions or visual tricks used in the theatre, film, television, video game A video game is an electronic game that involves interaction with a user interface or inpu ...
s in movies,
advertising Advertising is a marketing Marketing is the process of intentionally stimulating demand for and purchases of goods and services; potentially including selection of a target audience; selection of certain attributes or themes to emphasi ...

advertising
and technical manuals, often called DCC
digital content creation Content creation is the contribution of information Information is processed, organised and structured data. It provides context for data and enables decision making process. For example, a single customer’s sale at a restaurant is data ...
. The modern ubiquity and power of computers means that even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of the 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in
computational geometry Computational geometry is a branch of computer science devoted to the study of algorithms which can be stated in terms of geometry. Some purely geometrical problems arise out of the study of computational geometric algorithms, and such problems ar ...
,
computer graphics Computer graphics deals with generating images with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, cell phone and computer displays, and many specialized applications. A great dea ...

computer graphics
(both hardware and software), and
discrete differential geometryDiscrete differential geometry is the study of discrete counterparts of notions in differential geometry Differential geometry is a Mathematics, mathematical discipline that uses the techniques of differential calculus, integral calculus, linear a ...
. The design of
geometric model __NOTOC__ Geometric modeling is a branch of applied mathematics Applied mathematics is the application of mathematical methods by different fields such as physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epist ...
s for object shapes, in particular, is occasionally called ''computer-aided geometric design'' (''CAGD'').


History


Overview of CAD software

Starting around the mid-1960s, with the IBM Drafting System, computer-aided design systems began to provide more capability than just an ability to reproduce manual drafting with electronic drafting, the cost-benefit for companies to switch to CAD became apparent. The benefits of CAD systems over manual drafting are the capabilities one often takes for granted from computer systems today; automated generation of bills of materials, auto layout in
integrated circuits An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuit 200px, A circuit built on a printed circuit board (PCB). An electronic circuit is composed of indiv ...

integrated circuits
, interference checking, and many others. Eventually, CAD provided the designer with the ability to perform engineering calculations. During this transition, calculations were still performed either by hand or by those individuals who could run computer programs. CAD was a revolutionary change in the engineering industry, where draftsmen, designers, and engineering roles begin to merge. It did not eliminate departments as much as it merged departments and empowered draftsmen, designers, and engineers. CAD is an example of the pervasive effect computers were beginning to have on the industry. Current computer-aided design software packages range from 2D
vector Vector may refer to: Biology *Vector (epidemiology) In epidemiology Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and risk factor, determinants of health and disease conditions in defined pop ...
-based drafting systems to 3D
solid Solid is one of the four fundamental states of matter 4 (four) is a number A number is a mathematical object A mathematical object is an abstract concept arising in mathematics. In the usual language of mathematics, an ''object'' is an ...
and
surface File:Water droplet lying on a damask.jpg, Water droplet lying on a damask. Surface tension is high enough to prevent floating below the textile. A surface, as the term is most generally used, is the outermost or uppermost layer of a physical obje ...
modelers. 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 mathematical modeling. CAD technology 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). CAD is mainly used for detailed engineering of 3D models 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. It can also be used to design objects such as jewelry, furniture, appliances, etc. Furthermore, many CAD applications now offer advanced rendering and animation capabilities so engineers can better visualize their product designs.
4D BIM Building information modeling (BIM) is a process supported by various tools, technologies and contracts involving the generation and management of digital representations of physical and functional characteristics of places. Building information ...
is a type of virtual construction engineering simulation incorporating time or schedule-related information for project management. CAD has become an especially important technology within the scope of
computer-aided technologies Illustration of the interaction of the various computer-aided technologies. Computer-aided technologies (CAx) is the use of computer technology to aid in the design, analysis, and manufacture of products. Advanced CAx tools merge many different a ...
, with benefits such as lower product development costs and a greatly shortened
design cycle A decision cycle is a sequence of steps used by an entity on a repeated basis to Decision making, reach and implement decisions and to learn from the results. The "decision cycle" phrase has a history of use to broadly categorize various methods of ...

design cycle
. CAD enables designers to layout and develop work on screen, print it out and save it for future editing, saving time on their drawings.


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 In industry, product lifecycle management (PLM) is the process of managing the entire lifecycle of a product from its inception through the engineering, design, and manufacture, as well as the service and disposal of manufactured products. PLM ...

product lifecycle management
(PLM) processes, and as such is used together with other tools, which are either integrated modules or stand-alone products, such as: *
Computer-aided engineering Computer-aided engineering (CAE) is the broad usage of computer software Software is a collection of Instruction (computer science), instructions and data (computing), data that tell a computer how to work. This is in contrast to Computer har ...
(CAE) and
finite element analysis The finite element method (FEM) is a widely used method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, ...
(FEA, FEM) *
Computer-aided manufacturing Computer-aided manufacturing (CAM) also known as Computer-aided Modeling or Computer-aided Machining is the use of software to control machine tools and related ones in the manufacturing of work pieces. This is not the only definition for CAM, b ...
(CAM) including instructions to
computer numerical control Numerical control (also computer numerical control, and commonly called CNC) is the automated control of machining truck of the US Army with machinists working on automotive parts Machining is a process in which a material (often metal) is cut ...
(CNC) machines *
Photorealistic rendering __NOTOC__ 250px, The Indigo Renderer is unbiased. This 2009 render is of a German country road. Within the field of computer graphics, unbiased rendering refers to any rendering technique that does not introduce systematic error, or bias, int ...

Photorealistic rendering
and motion simulation. *Document management and
revision control In software engineering Software engineering is the systematic application of engineering approaches to the software development, development of software. A software engineer is a person who applies the principles of software engineering to d ...
using
product data managementProduct data management (PDM) or Product information management (PIM) is the business function often within product lifecycle management (PLM) that is responsible for the management and publication of product data. In software engineering, this is ...
(PDM) CAD is also used for the accurate creation of photo simulations that are often required in the preparation of environmental impact reports, in which computer-aided designs of intended buildings are superimposed into photographs of existing environments to represent what that locale will be like, where the proposed facilities are allowed to be built. Potential blockage of view corridors and shadow studies are also frequently analyzed through the use of CAD. CAD has been proven to be useful to engineers as well. Using four properties which are history, features,
parameterization In mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory), mathematical structure, structure (algebra), space (geometry), and calculus, change (mathematical analysis, analysis). It ...
, and high-level constraints. The construction history can be used to look back into the model's personal features and work on the single area rather than the whole model. Parameters and constraints can be used to determine the size, shape, and other properties of the different modeling elements. The features in the CAD system can be used for the variety of tools for measurement such as tensile strength, yield strength, electrical, or electromagnetic properties. Also its stress, strain,
timing Timing is the time when something happens or the spacing of events in time. "Timing" also means the tracking of time when an event is happening in time. Good timing is having waited for the right moment to match parts that belong together. Timing m ...
, or how the element gets affected in certain temperatures, etc.


Types

There are several different types of CAD, each requiring the operator to think differently about how to use them and 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 (not often used today). 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 add 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'' are created in a way analogous to manipulations of real-world objects (not often used today). Basic three-dimensional geometric forms (prisms, cylinders, spheres, rectangle) have solid volumes added or subtracted from them as if assembling or cutting real-world objects. Two-dimensional projected views can easily be generated from the models. Basic 3D solids don't usually includes tools to easily allow the motion of the components, set there limits to their motion, or identify interference between components. There are two types of ''3D
solid modeling Solid modeling (or modelling) is a consistent set of principles for mathematical and computer modeling of three-dimensional solids. Solid modeling is distinguished from related areas of geometric modeling and computer graphics by its emphasis o ...
'' * ''Parametric modeling'' allows the operator to use what is referred to as "design intent". The objects and features are created modifiable. Any future modifications can be made by changing on how the original part was created. If a feature was intended to be located from the center of the part, the operator should locate it from the center of the model. The feature could be located using any geometric object already available in the part, but this random placement would defeat the design intent. If the operator designs the part as it functions the parametric modeler is able to make changes to the part while maintaining geometric and functional relationships. * '' Direct or explicit modeling'' provide the ability to edit geometry without a history tree With direct modeling, once a sketch is used to create geometry the sketch is incorporated into the new geometry and the designer just modifies the geometry without needing the original sketch. As with parametric modeling, direct modeling has the ability to include the relationships between selected geometry (e.g., tangency, concentricity). The top-end systems offer the capabilities to incorporate more organic, aesthetic and ergonomic features into the designs. Freeform surface modeling 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.


Technology

Originally software for CAD systems was developed with computer languages such as
Fortran Fortran (; formerly FORTRAN) is a general-purpose, compiled language, compiled imperative programming, imperative programming language that is especially suited to numerical analysis, numeric computation and computational science, scientific com ...

Fortran
,
ALGOL Algol , designated Beta Persei (β Persei, abbreviated Beta Per, β Per), known colloquially as the Demon Star, is a bright multiple star in the constellation A constellation is an area on the celestial s ...
but with the advancement of
object-oriented programming Object-oriented programming (OOP) is a programming paradigm Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mai ...
methods this has radically changed. Typical modern parametric feature-based modeler and
freeform surface Freeform surface modelling is a technique for engineering freeform surfaces with a CAD or CAID system. The technology has encompassed two main fields. Either creating aesthetic surfaces (class A surfacesIn automotive design, a class A surface is ...
systems are built around a number of key C modules with their own
API In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and so ...
s. A CAD system can be seen as built up from the interaction of a
graphical user interface The graphical user interface (GUI "UI" by itself is still usually pronounced . or ) is a form of user interface In the industrial design Industrial design is a process of design A design is a plan or specification for the construction ...
(GUI) with
NURBS Non-uniform rational basis spline (NURBS) is a mathematical model using (B-splines) that is commonly used in for representing curves and . It offers great flexibility and precision for handling both analytic (defined by common mathematical e) an ...
geometry or
boundary representation In solid modeling and computer-aided design, boundary representation—often abbreviated as B-rep or BREP—is a method for representing shapes using the limits. A solid is represented as a collection of connected surface elements, which ...
(B-rep) data via a
geometric modeling kernelA geometric modeling kernel is a 3D solid modeling software component used in computer-aided design Computer-aided design (CAD) is the use of computer A computer is a machine that can be programmed to carry out sequences of arithmetic or ...
. A geometry constraint engine may also be employed to manage the associative relationships between geometry, such as wireframe geometry in a sketch or components in an assembly. Unexpected capabilities of these associative relationships have led to a new form of
prototyping A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics Semantics (from grc, σημαντικός ''sēmantikós'', "significant") ...

prototyping
called
digital prototyping Digital Prototyping gives conceptual design, engineering, manufacturing, and sales and marketing departments the ability to virtually explore a complete product before it's built. Industrial designers, manufacturers, and engineers use Digital Proto ...
. In contrast to physical prototypes, which entail manufacturing time in the design. That said, CAD models can be generated by a computer after the physical prototype has been scanned using an
industrial CT scanning Industrial computed tomography (CT) scanning is any computer-aided tomographic process, usually X-ray computed tomography, that uses irradiation Irradiation is the process by which an object is exposed to radiation upThe international sym ...
machine. Depending on the nature of the business, digital or physical prototypes can be initially chosen according to specific needs. Today, CAD systems exist for all the major platforms (
Windows Microsoft Windows, commonly referred to as Windows, is a group of several proprietary {{Short pages monitor