i don't know any formats, so i just wrote my own. you could try doing that...

From what I can tell, most game companies end up creating their own format. A lot of them end up creating a plug-in for 3D Studio MAX to export 3D objects to their format.

What file format should I use for objects in my D3DIM project?

The eaisest way to go is to use the file format of your modeling program that way there are no intermediate steps from modeling to using the model in your program.

But if you want a programming exercise on converting file formats or you want additional information in the object file that the modeling program doesnt support your time will be well spent.

For a real simple file format you can use something like:

3DobjectV001A (header and version info)
triangle (object name)
1 (number of materials)
1.000 1.000 1.000 (material RGB)
1.000 1.000 1.000 (material Specular)
1.000 1.000 1.000 (material Emmisive)
texture.bmp (texture filename)
3 (number of vertices)
0.0 0.0 0.0 0.0 0.0 (vertex list : x,y,z,u,v)
1.0 1.0 0.0 1.0 0.5
2.0 0.0 0.0 0.0 1.0
1 (number of faces)
0 1 2 (face list - indexes into the vertex list)

You can add what ever you want to your own file format like object attributes - weight, hitpoints, object type - weapon,food,money, ect.
Another cool idea that you can do with your own conversion program is use tagging.
In your modeling program suppose you are creating a building for your 3d environment. You could use special name prefixes on a small box placed in a corner of a room to specify that a script should be run or that a sound should be played when the player reaches this box (which of course is not rendered its only a trigger).

[This message has been edited by emfb (edited September 16, 1999).]