Computer-aided design
Computer-aided design (CAD) is the use of computers (or workstations) to aid in the creation, modification, analysis, or optimization of a design.[1]: 3 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.[1]: 4 Designs made through CAD software help protect products and inventions when used in patent applications. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The terms computer-aided drafting (CAD) and computer-aided design and drafting (CADD) are also used.[2]
Its use in designing electronic systems is known as
CAD software for mechanical design uses either
CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) space.[4][5]: 71, 106
CAD is an important
The design of
Overview
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
- finite element analysis(FEA, FEM)
- computer numerical control(CNC) machines
- Photorealistic renderingand motion simulation
- Document management and revision control using product data management(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.[8]
Types
There are several different types of CAD,[9] each requiring the operator to think differently about how to use them and design their virtual components in a different manner. Virtually all of CAD tools rely on constraint concepts that are used to define geometric or non-geometric elements of a model.
2D CAD
There are many producers of the lower-end 2D sketching systems, including a number of free and open-source programs. These provide an approach to the drawing process where scale and placement on the drawing sheet can easily be adjusted in the final draft as required, unlike in hand drafting.
3D CAD
3D wireframe is an extension of 2D drafting into a three-dimensional space. 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. Basic three-dimensional geometric forms (e.g., prisms, cylinders, spheres, or rectangles) 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 do not usually include tools to easily allow the motion of the components, set their limits to their motion, or identify interference between components.
There are several types of 3D solid modeling
- Parametric modelingallows 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 it is incorporated into the new geometry, and the designer only has to modify the geometry afterward 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).
- Assembly modelling is a process which incorporates results of the previous single-part modelling into a final product containing several parts. Assemblies can be hierarchical, depending on the specific CAD software vendor, and highly complex models can be achieved (e.g. in building engineering by using computer-aided architectural design software)[10]: 539
Freeform CAD
Top-end CAD systems offer the capability 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
Unexpected capabilities of these associative relationships have led to a new form of
Today, CAD systems exist for all the major platforms (
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 that 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
Software
Starting with the IBM Drafting System in the mid-1960s, computer-aided design systems began to provide more capabilitties than just an ability to reproduce manual drafting with electronic drafting, and the
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).[12]
CAD is mainly used for detailed design 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.
CAD has become an especially important technology within the scope of
License management software
In the 2000s, some CAD system software vendors shipped their distributions with a dedicated license manager software that controlled how often or how many users can utilize the CAD system.[5]: 166 It could run either on a local machine (by loading from a local storage device) or a local network fileserver and was usually tied to a specific IP address in latter case.[5]: 166
List of software packages
CAD software enables engineers and architects to design, inspect and manage engineering projects within an integrated
Based on market statistics,
Commercial software
- AC3D
- Alibre Design
- ArchiCAD (Graphisoft)
- AutoCAD (Autodesk)
- Autodesk Inventor
- AxSTREAM
- BricsCAD
- CATIA (Dassault Systèmes)
- Cobalt
- CorelCAD
- Fusion 360 (Autodesk)
- IntelliCAD
- IRONCAD
- KeyCreator (Kubotek)
- Landscape Express
- MEDUSA
- MicroStation (Bentley Systems)
- Modelur (AgiliCity)
- Onshape
- Pro/ENGINEER)
- PunchCAD
- Remo 3D
- Revit (Autodesk)
- Rhinoceros 3D
- Siemens NX
- SketchUp
- Solid Edge (Siemens)
- SolidWorks (Dassault Systèmes)
- SpaceClaim
- T-FLEX CAD
- TranslateCAD
- TurboCAD
- Vectorworks (Nemetschek)
Open-source software
Freeware
- BricsCAD Shape
- TiffinCAD
- Tinkercad (successor to Autodesk 123D)
CAD kernels
- ACIS by Spatial
- C3D Toolkit by C3D Labs
- Open CASCADEOpen Source
- Parasolid by Siemens
- ShapeManager by Autodesk
See also
- 3D computer graphics – Graphics that use a three-dimensional representation of geometric data
- 3D printing – Additive process used to make a three-dimensional object
- Additive Manufacturing File Format– Open standard for describing objects for additive manufacturing processes such as 3D printing
- Algorithmic art – Art genre
- CAD standards – type of technical standard
- CAD library - cloud based repository of 3D models or parts
- Coarse space (numerical analysis) – reduced representation of a numerical problem
- Comparison of 3D computer graphics software
- Comparison of CAD, CAM, and CAE file viewers
- Comparison of computer-aided design software
- Comparison of EDA software (electronic design automation)
- Computer-aided industrial design – Subset of computer-aided design
- Digital architecture – Architecture using digital technology
- Digital twin – Digital replica of a living or non-living physical entity
- Electronic design automation – Software for designing electronic systems
- Engineering optimization – Techniques for optimization
- Finite element method – Numerical method for solving physical or engineering problems
- ISO 128 – International standard about the graphical representation of objects on technical drawings
- ISO 10303 – ISO standard (STEP)
- List of computer-aided engineering software
- Model-based definition – Annotating computer-aided design models
- Molecular design software – CAD software for molecular-level engineering, modelling, and analysis
- Open-source hardware – Hardware from the open-design movement
- Rapid prototyping – Group of techniques to quickly construct physical objects
- Responsive computer-aided design – Approach to computer-aided design
- Space mapping – Design optimization methodology
- Surrogate model – Engineering model
- System integration – Bringing together component sub-systems into one system
- Virtual prototyping – Computer-simulated prototype development
- Virtual reality – Computer-simulated experience
References
- ^ ISBN 978-8120333420.
- ISBN 978-0962916595.
- ISBN 978-1111309572.
- ISBN 978-0-444-51104-1.
- ^ OCLC 50868192.
- ISBN 978-0-9728482-7-5.
- ISBN 1-55860-737-4.
- ^ "Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM)". Inc.com. Retrieved 2020-04-30.
- ^ "3D Feature-based, Parametric Solid Modeling". EngineersHandbook.com. Archived from the original on 2012-11-18. Retrieved 2012-03-01.
- ISBN 978-0-85729-259-9.
- ^ "What is a CAD Workstation? Definition, Uses and More". Computer Tech Reviews. 2019-11-21. Retrieved 2020-04-30.
- ^ Jennifer Herron (2010). "3D Model-Based Design: Setting the Definitions Straight". MCADCafe.
- ^ The Big 6 in CAD/CAE/PLM software industry (2011), CAEWatch, September 12, 2011
- ^ van Kooten, Michel (2011-08-23). "GLOBAL SOFTWARE TOP 100 – EDITION 2011". Software Top 100.
- ^ List of mechanical CAD softwares Archived 2020-07-28 at the Wayback Machine, BeyondMech
External links
- MIT 1982 CAD lab
- Learning materials related to Computer-aided design at Wikiversity
- Learning materials related to Computer-aided Geometric Design at Wikiversity