I believe that descriptions of 3D objects are significantly different from
images that it would do noone any good to lump them together.
I look at this with the question, "What kinds of things can we do to these
files", for an image the answers are things like display, scale, convert to
another image etc, in many cases a 2D display may be willing to accept an
image of any of several sub-types. On receiving an unknown image, launching
a generic viewer (like xv) may make sense etc.
The same answers apply to the disjoint set of 3D files, for example DXF,
RenderWare, VRML, ACE, these describe a 3D object (not neccessarily a
particular view on it), many tools can read one of the formats and convert
to the others. Common actions include viewing from different angles,
rotating, moving through them etc.
I think these kind of reasons make sense to use a seperate main type.
- Mitra
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Mitra mitra@path.net
Internet Consulting (415)488-0944
<http://www.path.net/mitra> fax (415)488-0988