Computer-aided design (CAD) is the use of computers (or workstations) to aid in the creation, modification, analysis, or optimization of a design. CAD 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. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD (for Computer Aided Design and Drafting) is also used.
Its use in designing electronic systems is known as electronic design automation (EDA). In mechanical design it is known as mechanical design automation (MDA) or computer-aided drafting (CAD), which includes the process of creating a technical drawing with the use of 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 showing the overall appearance of designed objects. However, it involves more than just shapes. As in the manual drafting of technical and engineering drawings, the output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions.
CAD is an important industrial art extensively used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prosthetics, and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising and technical manuals, often called DCC digital content creation. 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, computer graphics (both hardware and software), and discrete differential geometry.
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 Bill of Material, auto layout in 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 draftsman, designers and engineers. CAD is an example of the pervasive effect computers were beginning to have on industry. Current computer-aided design software packages range from 2D vector-based drafting systems to 3D solid and surface 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 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, with benefits such as lower product development costs and a greatly shortened 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.
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) processes, and as such is used together with other tools, which are either integrated modules or stand-alone products, such as:
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, parametrization, 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 or how the element gets affected in certain temperatures, etc.
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 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 are created in a way analogous to manipulations of real-world objects (not often used today). Basic three-dimensional geometric forms (prisms, cylinders, spheres, and so on) 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 include tools to easily allow motion of components, set limits to their motion, or identify interference between components.
There are two types of 3D solid modeling
Top end systems offer the capabilities to incorporate more organic, aesthetics and ergonomic features into 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.
Originally software for CAD systems was developed with computer languages such as Fortran, ALGOL but with the advancement of object-oriented programming methods this has radically changed. Typical modern parametric feature-based modeler and freeform surface systems are built around a number of key C modules with their own APIs. A CAD system can be seen as built up from the interaction of a graphical user interface (GUI) with NURBS geometry or boundary representation (B-rep) data via a geometric modeling kernel. 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 called digital prototyping. 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 machine. Depending on the nature of the business, digital or physical prototypes can be initially chosen according to specific needs.
Currently, no special hardware is required for most CAD software. However, some CAD systems can do graphically and computationally intensive tasks, so a modern graphics card, high speed (and possibly multiple) CPUs and large amounts of RAM may be 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.Technologies which in the past were limited to larger installations or specialist applications have become available to a wide group of users. These include the CAVE or HMDs and interactive devices like motion-sensing technology
CAD software enables engineers and architects to design, inspect and manage engineering projects within an integrated graphical user interface (GUI) on a personal computer system. Most applications support solid modeling with boundary representation (B-Rep) and NURBS geometry, and enable the same to be published in a variety of formats. A geometric modeling kernel is a software component that provides solid modeling and surface modeling features to CAD applications.
Based on market statistics, commercial software from Autodesk, Dassault Systems, Siemens PLM Software, and PTC dominate the CAD industry. The following is a list of major CAD applications, grouped by usage statistics.
Designers have long used computers for their calculations. Digital computers were used in power system analysis or optimization as early as proto-"Whirlwind" in 1949. Circuit design theory, or power network methodology would be algebraic, symbolic, and often vector-based. Examples of problems being solved in the mid-1940s to 50s include: servo motors controlled by generated pulse (1949), a digital computer with built-in computer operations to automatically co-ordinate transforms to compute radar related vectors (1951) and the essentially graphic mathematical process of forming a shape with a digital machine tool (1952). These were accomplished with the use of computer software. The man credited with coining the term CAD, Douglas T. Ross, stated, "As soon as I saw the interactive display equipment," [being used by radar operators 1953] he saw it would be just what his SAGE related data reduction group needed. With the Lincoln Lab people, they were the only ones who used the big, complex display systems put in for the pre-SAGE, Cape Cod system. But "we used it for our own personal workstation.". The designers of these very early computers built utility programs so that programmers could debug programs using flowcharts on a display scope with logical switches that could be opened and closed during the debugging session. They found that they could create electronic symbols and geometric figures to be used to create simple circuit diagrams and flowcharts. And that an object once drawn could be reproduced at will, its orientation, Linkage [ flux, mechanical, lexical scoping ] or scale changed. This suggested numerous possibilities to them. It took ten years of interdisciplinary development work before SKETCHPAD sitting on evolving math libraries emerged from MIT's labs. Additional developments were carried out in the 1960s within the aircraft, automotive, industrial control and electronics industries in the area of 3D surface construction, NC programming, and design analysis, 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 Robert Issac Newton from Pawtucket, Rhode Island. 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 Bézier, 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.
The invention of the 3D CAD/CAM is attributed to a French engineer, Pierre Bézier (Arts et Métiers ParisTech, Renault). After his mathematical work concerning surfaces, he developed UNISURF, between 1966 and 1968, to ease the design of parts and tools for the automotive industry. Then, UNISURF became the working base for the following generations of CAD software.
It is argued that a turning point was the development of the SKETCHPAD system at MIT by Ivan Sutherland (who later created a graphics technology company with 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. Sutherland presented his paper Sketchpad: A Man-Machine Graphical Communication System in 1963 at a Joint Computer Conference having worked on it as his PhD thesis paper with Doctoral advisor Claude Shannon . Quoting, "For drawings where motion of the drawing or analysis of a drawn problem is of value to the user, Sketchpad excels. For highly repetitive drawings or drawings where accuracy is required, Sketchpad is sufficiently faster than conventional techniques to be worthwhile. For drawings which merely communicate with shops, it is probably better to use conventional paper and pencil." Over time efforts would be directed toward the goal of having the designers drawings communicate not just with shops but with the shop tool itself. This goal would be a long time arriving.
The 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, a joint project of GM (Patrick J. Hanratty) and IBM (Sam Matsa, Doug Ross's MIT APT research assistant) to develop a prototype system for design engineers DAC-1 (Design Augmented by Computer) 1964; Lockheed projects; Bell GRAPHIC 1 and Renault.
One of the most influential events in the development of CAD was the founding of MCS (Manufacturing and Consulting Services Inc.) in 1971 by Patrick 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 desktop computers was the impetus for almost universal application in all areas of construction.
CAD implementations have evolved dramatically since then. Initially, with 3D 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 modeling 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 1987, 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) Parasolid (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 and TriSpective (later known as IRONCAD) in 1995, Solid Edge (then Intergraph) in 1996 and Autodesk Inventor in 1999. An independent geometric modeling kernel has been evolving in Russia since the 1990s.
Algorithms-Aided Design (AAD) is the use of specific algorithms-editors to assist in the creation, modification, analysis, or optimization of a design. The algorithms-editors are usually integrated with 3D modeling packages and read several programming languages, both scripted or visual (RhinoScript®, Grasshopper®, MEL®, C#, Python®). The Algorithms-Aided Design allows designers to overcome the limitations of traditional CAD software and 3D computer graphics software, reaching a level of complexity which is beyond the human possibility to interact with digital objects. The acronym appears for the first time in the book AAD Algorithms-Aided Design, Parametric Strategies using Grasshopper, published by Arturo Tedeschi in 2014.AutoQ3D Community
AutoQ3D Community is a cross-platform CAD software, suited for 3D modeling and texturing. The main objective of this software development is to take away the hassle and complexity for sketching and drawing in 3D. AutoQ3D Community is not a professional CAD program and it is targeted at beginners who want to make rapid 3D designs. It offers plenty of features but is relatively simple to learn and use.
AutoQ3D Community is written in C++ using the Qt application framework and supports the OpenGL API.BRL-CAD
BRL-CAD is a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system. It includes an interactive geometry editor, ray tracing support for graphics rendering and geometric analysis, computer network distributed framebuffer support, scripting, image-processing and signal-processing tools. The entire package is distributed in source code and binary form.
Although BRL-CAD can be used for a variety of engineering and graphics applications, the package's primary purpose continues to be the support of ballistic and electromagnetic analyses. In keeping with the Unix philosophy of developing independent tools to perform single, specific tasks and then linking the tools together in a package, BRL-CAD is basically a collection of libraries, tools, and utilities that work together to create, raytrace, and interrogate geometry and manipulate files and data. In contrast to many other 3D modelling applications, BRL-CAD primarily uses CSG rather than boundary representation. This means BRL-CAD can "study physical phenomena such as ballistic penetration and thermal, radiative, neutron, and other types of transport" It does also support boundary representation.The BRL-CAD libraries are designed primarily for the geometric modeler who also wants to tinker with software and design custom tools. Each library is designed for a specific purpose: creating, editing, and raytracing geometry, and image handling. The application side of BRL-CAD also offers a number of tools and utilities that are primarily concerned with geometric conversion, interrogation, image format conversion, and command-line-oriented image manipulation.BricsCAD
BricsCAD is a software application for computer-aided design (CAD), developed by Bricsys nv. The company was founded in 2002 by Erik de Keyser, a longtime CAD entrepreneur. In 2011 Bricsys acquired the intellectual property rights from Ledas for constraints-based parametric design tools, permitting the development of applications in the areas of direct modeling and assembly design. Bricsys is headquartered in Ghent, Belgium, has additional development centers in Nizhny Novgorod and Novosibirsk, Russia; Bucharest, Romania and Singapore. Bricsys is a founding member of the Open Design Alliance, and joined the BuildingSMART International consortium in December of 2016.
In 2018, Bricsys nv was acquired in full by Hexagon AB of Sweden.CADKEY
CADKEY is a 2D/3D mechanical CAD (computer aided design or computer aided drafting) software application released for various DOS, UNIX, and Microsoft Windows operating systems. Originally released for DOS in 1984, CADKEY was among the first CAD programs with 3D capabilities for personal computers.Comparison of computer-aided design editors
The table below provides an overview of computer-aided design (CAD) software. It does not judge power, ease of use, or other user-experience aspects. The table does not include software that is still in development (beta software). For all-purpose 3D programs, see Comparison of 3D computer graphics software.
CAD refers to a specific type of drawing and modeling software application that is used for creating designs and technical drawings. These can be 3D drawings or 2D drawings (like floor plans).Computer-Aided Design Technical Committee
The Computer-Aided Design Technical Committee (more commonly known as CANDE, for Computer-Aided Network DEsign) is a Technical Committee of IEEE Circuits and Systems Society(IEEE-CAS), one of the many societies that comprise the IEEE.
The purpose of CANDE is to promote research and best practices in the
development and use of computer-aided design software in the design and test of
microelectronic circuits and systems.Electric (software)
The Electric VLSI Design System is an EDA tool written in the early 1980s by Steven M. Rubin. Electric is used to draw schematics and to do integrated circuit layout.
It can also handle hardware description languages such as VHDL and Verilog. The system has many analysis and synthesis tools, including Design rule checking, Simulation, Routing, Layout vs. Schematic, Logical Effort, and more.
Electric is currently part of the GNU project and has been developed in Java and distributed as free and open-source software, subject to the requirements of the GNU General Public License (GPL), version 3 or any later.FreeCAD
FreeCAD is a free and open-source (under the LGPLv2+ license) general-purpose parametric 3D CAD modeler and a building information modeling (BIM) software with finite-element-method (FEM) support. FreeCAD is aimed directly at mechanical engineering product design but also expands to a wider range of uses around engineering, such as architecture or electrical engineering. FreeCAD can be used interactively, or its functionality can be accessed and extended using the Python programming language and is currently in a beta stage of development.LibreCAD
LibreCAD is a free computer-aided design (CAD) application for 2D design. It works on Linux, macOS, Unix and Windows operating systems.LibreCAD was developed as a fork of QCad Community Edition. The GUI of LibreCAD is based on Qt4 libraries, so it runs on several platforms in the same way.Most of the interface and handle concepts are analogous to AutoCAD, making it easier to use for users with experience of this type of commercial CAD application.
LibreCAD uses the AutoCAD DXF file format internally for import and save files, as well as allowing export to many other file formats.OpenSCAD
OpenSCAD is a free software application for creating solid 3D CAD (computer-aided design) objects. It is a script-only based modeller that uses its own description language; parts can be previewed, but it cannot be interactively selected or modified by mouse in the 3D view. An OpenSCAD script specifies geometric primitives (such as spheres, boxes, cylinders, etc.) and defines how they are modified and combined (for instance by intersection, difference, envelope combination and Minkowski sums) to render a 3D model. As such, the program does constructive solid geometry (CSG). OpenSCAD is available for Windows, Linux and OS X.Open Cascade Technology
Open Cascade Technology (OCCT), formerly called CAS.CADE, is an open-source software development platform for 3D CAD, CAM, CAE, etc. that is developed and supported by Open Cascade SAS.QCad
QCAD is a free computer-aided design (CAD) software application for 2D design and drafting. It is available for Linux, Apple macOS, Unix and Microsoft Windows. The QCAD GUI is based on the Qt framework.
QCAD is released under the GNU General Public License. Precompiled packages are available for 32-bit and 64-bit GNU/Linux platforms, Microsoft Windows OS and macOS.
Some of the interface and concepts behind QCAD are similar to those of AutoCAD.
QCAD uses the AutoCAD DXF file format internally and to save and import files. AutoCAD DWG support is available as a commercial plugin.
Starting from version 3.7 QCAD is distributed as Professional Trial that work for a limited time, or as Community Edition as source code only, so users need to self compile.Rhinoceros 3D
Rhinoceros (typically abbreviated Rhino, or Rhino3D) is a commercial 3D computer graphics and computer-aided design (CAD) application software developed by Robert McNeel & Associates, an American, privately held, employee-owned company founded in 1980. Rhinoceros geometry is based on the NURBS mathematical model, which focuses on producing mathematically precise representation of curves and freeform surfaces in computer graphics (as opposed to polygon mesh-based applications).
Rhinoceros is used in processes of computer-aided design (CAD), computer-aided manufacturing (CAM), rapid prototyping, 3D printing and reverse engineering in industries including architecture, industrial design (e.g. automotive design, watercraft design), product design (e.g. jewelry design) as well as for multimedia and graphic design.Rhinoceros is developed for the Microsoft Windows operating system and OS X. A visual scripting language add-on for Rhino, Grasshopper, is developed by Robert McNeel & Associates.Siemens NX
NX, formerly known as "UG". In 2000 Unigraphics purchased SDRC I-DEAS and began an effort to integrate aspects of both software packages into a single product which became Unigraphics NX or NX. NX is an advanced high-end CAD/CAM/CAE, which has been owned since 2007 by Siemens PLM Software.It is used, among other tasks, for:
Design (parametric and direct solid/surface modelling)
Engineering analysis (static; dynamic; electro-magnetic; thermal, using the finite element method; and fluid, using the finite volume method).
Manufacturing finished design by using included machining modules.NX is a direct competitor to CATIA, Creo, Autodesk Inventor, and SolidWorks.SketchUp
SketchUp, formerly Google Sketchup, is a 3D modeling computer program for a wide range of drawing applications such as architectural, interior design, landscape architecture, civil and mechanical engineering, film and video game design. It is available as a web-based application, SketchUp Free, a freeware version, SketchUp Make, and a paid version with additional functionality, SketchUp Pro.SketchUp is owned by Trimble Inc., a mapping, surveying and navigation equipment company. There is an online library of free model assemblies (e.g. windows, doors, automobiles), 3D Warehouse, to which users may contribute models. The program includes drawing layout functionality, allows surface rendering in variable "styles", supports third-party "plug-in" programs hosted on a site called Extension Warehouse to provide other capabilities (e.g. near photo-realistic rendering) and enables placement of its models within Google Earth.SolveSpace
SolveSpace is a free libre and open source 2D and 3D CAD (computer-aided design) program. It is a constraint-based parametric modeler with simple mechanical simulation capabilities. Version 2.1 onward runs on Windows, Linux and macOS. It is developed by Jonathan Westhues and a community of volunteers.Tessellation (computer graphics)
In computer graphics, tessellation is used to manage datasets of polygons (sometimes called vertex sets) presenting objects in a scene and divide them into suitable structures for rendering. Especially for real-time rendering, data is tessellated into triangles, for example in OpenGL 4.0 and Direct3D 11.Virtual home design software
Virtual home design software is a type of computer-aided design software intended to help architects, designers, and homeowners preview their design implementations on-the-fly. These products differ from traditional homeowner design software and other online design tools in that they use HTML5 to ensure that changes to the design occur rapidly. This category of software as a service puts an emphasis on usability, speed, and customization.