CAD: “Computer Aided Design” is the use of computers for making digital drawings.

CAD drawings can be designed in a “Layout” with the goal to create an image for publication purposes. Such designed images can be printed to a PDF/A (PDF/A-1b: 2005 (RGB)). This preserves the visual purpose of the image and is an excellent solution for formatted images, but the digital drawing itself can no longer be imported into CAD; the image loses the further editable properties.

In practice, CAD is also often used for creating Vector graphics in formats specific to the CAD application. Despite the similarity, the guidelines for these file formats cannot simply be combined. This is because CAD formats can contain properties that are not supported by formats purely intended for vector images. Moreover, the export possibilities from CAD applications are limited.
If the nature of the CAD file as well as the application allows an export to SVG, this is recommended. This export must be carefully checked for completeness.

Preferred formats

• AutoCAD DXF version R12 (ASCII) (.dxf)
• SVG (.svg)

Non-preferred formats 

• Autocad DXF, version other than R12 (ASCII) (.dxf)
• DWG (.dwg)
• DGN (.dgn)