.i3d

The .i3d format is built on 3D Studio's .3ds, chunk for chunk, with a few of its own: UVs held per corner, bones, and its own ways with animation and see-through textures. The Source view lists its chunks.

What WebUVs reads

• Meshes and their UVs, from UV channels. Each corner of each face has its own UV there, as in an OBJ. A mesh can carry more than one channel: channel 1 holds the textures, and WebUVs works on it. Any other, such as one for lightmaps, stays as it is.
• Materials, with their textures. A "!" in a material's name keys out a color of its texture: see Opacity maps and color keys.
• The keyframer: the objects and bones, how they nest and where each stands, and any animation, played at 100 frames a second. See Timeline.

Some .i3d files are laid out as a .3ds is, one UV per vertex; WebUVs reads those too.

Saving it back

Pick its own I3D under Download As to save the file back with the UVs as they are now. Only a mesh's UV channel chunk is written afresh; its vertices, faces, materials, other channels and the keyframer stay byte for byte as they were.

As another kind of file

An .i3d model can be saved as OBJ and MTL or as a new .3ds. The menu lists what the new file leaves out, such as its bones and animation. Either way it's turned to stand up as that kind of file does, at the frame showing.

Good to know

Which way up an .i3d model stands depends on how its meshes were made: WebUVs guesses as it opens. See Orientation.