I've currently been fighting with a model made up of several meshes where half of the meshes are wound in the wrong order.

Is there any way to figure out if a polygon is wound clockwise or counter clockwise using the FBX SDK?

I've tried calling CheckIfVertexNormalsCCW on each mesh and it always returns 0 no matter if the winding is correct or not.

Part of me also wonders if our artist accidentally flipped the normals somehow.

Thoughts?

Cheers,
Tristan

Most likely they have an odd number negative scales applied to them reversing the winding order.

The half that are not showing up are probably reflected version of the opposite side.

If the scale of a mesh is negative for 1 or 3 axis, then flip the winding order.

Here are some threads about this from the Autodesk FBX forums.

http://area.autodesk.com/forum/autodesk-fbx/fbx-sdk/kfbxgeometryconvertertriangulateinplace/

http://area.autodesk.com/forum/autodesk-fbx/fbx-sdk/getting-polygonface-not-vertex-normal-data/

[Edited by - Doug Rogers on December 26, 2010 3:00:58 PM]