CAD standards

CAD standards are a set of guidelines for the appearance of computer-aided design drawings and for how CAD data is organized, most prominently in architecture and engineering. The standards are intended to improve productivity and to facilitate the interchange of information between different organizations and computer platforms.
In education, CAD standards may refer to skill requirements to be met for an individual's certification in CAD.

Background

Computer-aided design made its first appearance in the mid-1960s and brought rapid technological change to the drafting and design professions. CAD systems evolved alongside developments in computer hardware and software, resulting in a wide range of CAD products by the 1980s. Multiple, overlapping CAD standards resulted from the need to address different issues in organization, appearance, and sharing of CAD files.
In the United States, the American Institute of Architects introduced its popular CAD Layer Guidelines in 1990. The National CAD Standard was released in 1999, developed by the National Institute of Building Sciences for 2D CAD organization. This brought together independent standards of the AIA, the Construction Specifications Institute, and the US Department of Defense Tri-Services CAD plotting standards. In data standardization, the International Alliance for Interoperability was founded in 1995, with some 600 software firms as members. This organization developed and released a number of open-data object-oriented data sets which were adopted by software companies. Compliant software could share data, allowing, for example, spatial planning data from a spreadsheet to be used by other programs to generate a floorplan, a 3D CAD model, or a building cost estimate.
More specific CAD standards are often set among organizations, such as a manufacturing company and its suppliers, to ensure efficiency and accuracy.

Architecture standards

CAD layer standards

Most common:

National CAD Standard, a US standard which combines:
*AIA CAD Layer Guidelines, 2nd edition
*Construction Specifications Institute's Uniform Drawing System
*Department of Defense's Tri-Services CAD Center's plotting Standards.
Architecture/Engineering/Construction CAD Standard, used for standardization across US Department of Defense facilities.
BS 1192, which relies heavily on the UK Code of Procedure for the Construction Industry
*AEC, an adaptation of BS-1192 based on Uniclass.
ISO 13567-1/3, International standard, commonly used in Northern Europe;
*SIA 2014, Swiss standard for engineers and architects, based on ISO 13567.
*ÖNORM A 6240-4, Austrian standard for digital documentation in technical drawings, based on ISO 13567.

Samples of standardized layers:

Line-thickness

Thickness for pens and plot: Gray, Red, White, Yellow, Magenta, Blue, Green. In AutoCAD usually parts to be printed in black are drawn in 1 to 7 basic colors. Color layer: Green-Center, Magenta-Measure of length, and Blue-Hidden.

Description	Line thickness in mm	Color Codes
Outline	0.20 or 0.25	White, Cyan, Yellow, Blue
Hidden Line	0.00 or 0.05	Blue, Gray, 241
Center Line	0.10 or 0.15	Green, Red, Blue
Note	0.18 or 0.20	White, Cyan, Green, 41
Thin Line	0.00 or 0.05	Gray, 08, 111
Reference Line	0.000	Magenta, Gray
Hatch Line	0.000	Magenta, Green, Gray, red
Color-9 to 256	0.000
Dimension line
Leader Line with Arrows	0.000	Gray Color-9, or 8, Red
Text	0.18 or 0.20	Cyan, Green

Text and dimension

Heights:,,, .
Font styles: "Romans.shx – Romantic Simplex", "ISOCPEUR.ttf". Exceptional use of screen fonts.

Scales

2:1, 20:1, 200:1...
1:1, 1:10, 1:100...
in = 1 ft
in = 1 ft
in = 1 ft
in = 1 ft
in = 1 ft
1 in = 1 ft
in = 1 ft
3 in = 1 ft
6 in = 1 ft
1 ft = 1 ft

File naming standards

BS 1192: Discipline, Element, Drawing type, Unique number, Revision.

Samples: A22P012G.dwg.

Samples: ZE1G-124.dwg, XE1G-100.dwg

AEC : Project, Discipline, Zone, View, Level, Content, Sequential number ;

Samples: 1234-A-Off-P-M1-Furn-11c.dwg, A-P-01-Part, 1234-A-S-055.dgn, A-S-xx-AA.dwg, A-P-x-Grid.dgn, 1838-S-C-P-03.

Other local: Job number, Agent, Section, phase, sheet number, revision.

Samples: 0512-A-00A_-1-01-02.dwg
Job number, View, section, phase, revision
Samples: 123p0s2d0.dwg, 459s0BBD0.dgn.
it produces a large number of photos that could then be CAD into a file format.

Mechanical standards

Model-based definition

Model-based definition is a method of product specification using elements within 3D models as defined by the US standard ASME Y14.41-2012. ASME Y14.41-2012 is based upon ASME Y14.5-2009 symbols and definition methods, such as geometry dimensioning and tolerancing.
Subscribers of International Organization for Standardization have the standards ISO 1101 and ISO 16792 for model-based definition.

Geometry quality

VDA 4955

Product data quality

Product data quality is a field of product lifecycle management relating to the quality of product data, particularly the geometrical and organizational quality of CAD data. Checkers, software that analyze CAD data formats, are often employed before and after data translation.
The checkers can check the organization and quality of the data against internal company standards and international or industry standards.
These checkers can be built into specific CAD packages or work on a number of CAD file formats.
In 2006–07 Part 59 of STEP ISO 10303-59 Product data representation and exchange: Integrated generic resource: Quality of product shape data is under development. It defines how to represent quality criteria together with measurement requirements and representation of inspection results.