Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!sgi!gavin@krypton.SGI.COM
From: gavin@krypton.SGI.COM (Gavin Bell)
Newsgroups: comp.graphics
Subject: 3D object file formats
Keywords: file formats, 3D
Message-ID: <30686@sgi.SGI.COM>
Date: 14 Apr 89 02:16:08 GMT
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 49

I am looking for information on 3-D object file formats; if you have
a lot of experience with 3D formats, or know of any relevant
references, I would appreciate E-mail, or, if you think this might be
of general interest, a response in this newsgroup.

My general wants:

-- I want a format that allows me to express relations like "These
material properties are attached to these polygons", for example.  I
want the set of types to be extensible, but it should include at least
the following:
	polygons, vertices, colors, normals, material properties (i.e.
	index of refraction, diffuse, specular, etc.)
It should be easy to add:
	splines, nurbs, textures, CSG primitives, triangle meshes, etc.

-- I want a format that allows useful tools to be written:  i.e. a
filter that finds the normals for an object, a filter that
triangulates the polygons in an object, a filter that converts a file
from a CSG representation to a polygonal representation.  This means a
display-list type of format just isn't good enough.

I know about the following formats:
-- Dec's off file format.  Great for what it does, but too simple.

-- Princeton University Lincoln format.  A winged-edge format,
	definitely not easily extensible, concerned almost exclusively
	with topology.

-- Mathematica's format.  Quick and dirty.

-- At least 7 different formats used here at Silicon Graphics; most of
	them were written as one-time things, none of the do what I want
	them to.

-- Aliases object file format.  Specific to what their software is
	capable of.

-- Wavefront's object file format.  Specific to what their software
	does.

-- A couple of ray-tracer formats.  Specific to the kinds of
	objects/textures/etc that they support.

I am asking this since I would rather not invent Yet Another Object
File Format.  However, I haven't found anything appropriate.  Any
suggestions?

--gavin  (gavin@sgi.com)