[Maya2osg-users] Triangle winding question (maya usage)

[Jean-Sébastien G. <jea...@cm...>]

Hi guys,

This is a Maya usage question... Hope you don't mind.

Our modelers often create symmetric pieces by first creating half, then 
duplicating that half, scaling it by -1, reversing the normals and then 
freezing the transforms.

This seems to work fine, at least in Maya, except that I notice now that 
triangle winding (vertex order) is still inversed when they do that. 
This manifests itself in two ways in our realtime app: Lighting 
considers the wrong side of a face (light seems to come from the 
opposite side) and backface culling is reversed (faces are culled when 
looking from the outside instead of from the inside).

I wonder, is there a way in Maya to reverse the triangle winding? I can 
write a script (or search the net for one), but is there something built-in?

I was thinking of writing a script that would go through all polygons of 
a model and compare the "implicit normal" (calculate a normal using the 
vertex order in the triangle) to the saved normal (in the normal array) 
and if it doesn't point in roughly the same direction, reverse the 
vertex order. This assumes that the artist has made his normals all 
point in the correct direction, so the normals are used as reference to 
correct the triangle winding. I could then put this script on preExport 
in the plugin.

My question is really, do I have to do this myself or is there something 
already there I can use?

Thanks in advance,

J-S
-- 
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Jean-Sébastien Guay    jea...@cm...
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