VC6

VC6 is the format used for 2D and 3D drafting files in Graphite from Ashlar-Vellum. This was formerly known as Vellum, which used VLM files.

Identification
The files appear to start with the hex bytes. They are binary files.

Software
A free viewer can be downloaded in the publisher's site.

Samples
Some sample files can be found with the viewer above when you install it. The files are in  in the Windows version. (May vary by version)

Links

 * Graphite page in publisher's site
 * Wikidata: Ashlar-Vellum