# CAD standards

CAD standards are a set of guidelines for the appearance of computer-aided design (CAD) drawings should appear, to improve productivity and interchange of CAD documents between different offices and CAD programs, especially in architecture and engineering.

## Architecture standards
### CAD layer standards

Most common:
* BS 1192, which relies heavily on the Code of Procedure for the Construction Industry
* AIA Cad Layer Guidelines, 2nd edition (1997), has great usage in the USA;
* ISO 13567-1/3, International standard, common in Northern Europe;
* AEC (UK), an adaptation of BS-1192 based on Uniclass.
* A/E/C CAD Standard, Tri-service (USACE/Air Force/NAVFAC) CAD standard created/maintained by the CAD/BIM Technology Center for Facilities, Infrastructure, and Environment...
* SIA 2014 (1996), Swiss standard for engineers and architects, based on ISO 13567.
* ÖNORM A 6240-4 (2012), Austrian standard for digital documentation in technical drawings, based on ISO 13567.
Samples of standardized layers:
    A-B374--E- (ISO13567: agent Architect, element Roof window in SfB, presentation graphic element);
    A-37420-T2N01B113B23pro (ISO13567: agent Architect, element Roof Window in SfB, presentation Text#2, New part, floor 01, block B1, phase 1, projection 3D, scale 1:5(B), work package 23 and user definition "pro");
    A-G25---D-R (ISO13567: agent Architect, element wall in Uniclass, presentation dimensions, status Existing to be removed);
    A-G251-G-WallExtl-Fwd (AEC(UK): agent Architect, element External Wall in Uniclass, presentation graphic element, user definition "WallExtl" and view Forward);
    A210_M_ExtWall (BS1192: agent Architect, element External Wall in SfB, presentation model, user definition "ExtWall");
    A-E04---E- (ISO13567 SIA 2014: agent Architect, element Stair in SIA classification, presentation graphic element);
    A-WALL-FULL (AIA: agent Architect, element Wall, Full height).

### Line-thickness

Thickness for pens and plot: 0.13 mm Gray, 0.18 mm Red, 0.25 mm White, 0.35 mm Yellow, 0.50 mm Magenta, 0.70 mm Blue, 1.00 mm 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 |
| Out Line | 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: 2.5 mm, 3.5 mm, 5.0 mm, 7.0 mm (stroke thickness (lineweight) should be 0.1 of the character height). Font styles: "Romans.shx – Romantic Simplex", "ISOCPEUR.ttf". Exceptional use of screen fonts (arial, Times New Roman etc.).

### Scales

* 2:1, 20:1, 200:1 ...
* 1:1, 1:10, 1:100 ...
* 3⁄16 in = 1 ft
* 1⁄4 in = 1 ft
* 3⁄8 in = 1 ft
* 1⁄2 in = 1 ft
* 3⁄4 in = 1 ft
* 1 in = 1 ft
* 1+1⁄2 in = 1 ft
* 3 in = 1 ft (QUARTER SCALE)
* 6 in = 1 ft (HALF SCALE)
* 1 ft = 1 ft (FULL SCALE)

### File naming standards

* BS 1192:
Discipline (1 char), Element (2 char, using SfB Table 1 or Uniclass), Drawing type (1 char, P=preliminary, X=special/xref, L=layout, C=component, S=schedules, A=assembly drawings, K=co-ordination drawing), Unique number (3 char), Revision (1 char, A=emission, B,C,D...= revisions). Samples: A22P012G.dwg (architect, internal walls in SfB, preliminary design, sheet 012, revision G).
* AIA
* AEC
Samples: ZE1G-124.dwg, XE1G-100.dwg
* AEC (UK)
Project (unlimited char), Discipline (2 char max, recommended mandatory), Zone (optional), View (1 char, rec.mand.), Level (2 char, rec.mand.), Content (rec.mand.), Sequential number (up to 3 char); Samples: 1234-A-Off-P-M1-Furn-11c.dwg (project #1234, architect, office zone, plan, mezzanine 1, furnitures, version 1.1 revision c), A-P-01-Part (architect, plan, 1st floor, partitions), 1234-A-S-055.dgn (project #1234, architect, section, sheet 055), A-S-xx-AA.dwg (architect, section, full building, section AA), A-P-x-Grid.dgn (architect, plan, all floor, grid), 1838-S-C-P-03 (project 1838, structures, building C, plan, 3rd floor).
* Other local:
Job number (4 char), Agent (1 char), Section (4 char), phase (1 char), sheet number (2 char), revision (2 char) Samples: 0512-A-00A_-1-01-02.dwg Job number (3 char), View (2 char), section (2char), phase (1 char), revision (1 char) Samples: 123p0s2d0.dwg (job 1239, plan, 2nd floor, definitive drawing, emission), 459s0BBD0.dgn (job 123, section B, definitive drawing, emission). it produces a large number of photos that could then be CAD into a file format.

## Mechanical CAD standards
### Model-based definition

Model-based definition (MBD) is a method of product specification using elements within 3D models as defined by 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 (GD&T).
Subscribers of International Organization for Standardization (ISO) have the standards ISO 1101 and ISO 16792 for model-based definition.

### Geometry quality

VDA 4955

## Product Data Quality

PDQ is a field of PLM 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 2006/2007 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.