Verband des Automobilindustrie - VDAFS is a standard used for the transfer of freeform shapes.
It was conceived for the transfer of freeform surfaces and their supporting objects. This means the dimensions, layers, 2D geometry and text are left out. This file format was logged as a National Standard in Germany (DIN 66301). Alias uses version 2.0 of VDAFS.
The basic file structure of the VDAFS format has a header section which gives the general information about where, when, by who and how the file was created. After the header, the entities are described one after the other.
The entity description has the following structure:
There are a limited number of entity types that can be used in the VDAFS file. These entities only deal with the geometry and topology of elements.
Entity type | Description |
POINT | Point |
PSET | Point Sequence |
MDI | Point Vector Sequence (Master Dimension) |
CIRCLE | Circle/Arc |
CURVE | Curve |
SURF | Surface |
CONS | Curve on Surface |
FACE | Bounded Surface |
TOP | Topology of a Surface |
The only non-geometrical entities that can be used are the following:
Entity type | Description |
HEADER | Header |
$$ | Comment |
BEGINSET | Set - begin ~ group |
ENDSET | Set - end |
GROUP | Group |
TMAT | Transformation Matrix |
TLIST | Transformation List |
Because of this limited number of entities, compared to the 500+ of the IGES format, geometry is always defined using the same rules resulting in a lower number of errors. On the other hand, you lose a lot of information that was created in the originating system like layers but these can eventually be replaced by groups, colors, dimensions, and so on.