Sculpties UV maps

I've created a small program that generates sculpties starting from a "description" of the object to be created.

I can export it as a sculpt map for SL or as a .obj to be imported in a real modeler (say wings3D).

The geometry part of the .obj (vertices and faces) has been relatively easy but I'm having hard times with the UV map.

I understood UV coordinates ranges from 0.0 to 1.0 so I "sampled" a grid of 32x33 points at regular intervals and mapped (in the same order) each face to an UV triangle.

I must have missed something as the resulting UV map (as I see it when loaded in Wings3D) is not correct.

Does anyone have a description of how a .obj UV maps should be structured to work properly according SL rules?

Many thanks!

RD

You're right that the coordinates range from 0.0 to 10.. But UV coordinates are specified at each vertex. For a 32x32 bitmap you're always going to need 32x32 coordinate pairs. I'm not sure what you meant when you referred to sampling a grid of size 32x33.

As for what the coordinates should be, if the dimension doesn't wrap, you want 32 values equally spaced between 0 and 1, inclusive. So the values would be 0, 1/32, 2/31, ..., 31/31. But if the dimension wraps (producing 32 faces instead of 31), you want the values 0, 1/32, 2/32, ..., 31/32, so that the strip ftom 31/32 to 32/32 will be used for the face created by the wrap.

Does that make sense?

Thanks Omei! To see if I get it right, i've create a blog post with a summary of what I've understand about the UV mapping on sculpties.

I would really appreciate any comment or feedback (especially if I'm wrong )

http://a3dsculpt.blogspot.com/2008/12/uv-mapping-for-sculpties.html

Ok. I rewrote the export function in C and got it right now! Thanks everybody!

looks like the UV map has an error

Ach! Can you be more specific? I'll go checking again ....