Forum: Poser - OFFICIAL


Subject: material coming out black no matter what

diomede opened this issue on Aug 25, 2005 ยท 23 posts


an0malaus posted Fri, 26 August 2005 at 8:52 AM

Nice to see a quick fix there :-) @sixus1, the obj format can actually indirectly record vertex normals in two ways. One is the vn x y z lines which Poser doesn't need and the other is the face winding order which Poser uses to determine the vertex normal vectors using (I believe) the vector cross product of the two face edges adjacent to each vertex. The easiest way to remember which way the normal will face from the face vertex order is the "Right Hand Thumb Rule". With the fingers of your right hand curled round and your thumb extended, orient your fingers to point in the direction which follows the order the vertices are listed in the face f line. E.g. If they're listed clockwise, your thumb (and the normal vector) will point away from you. If they're anti-clockwise, the vector will be towards you. It is possible to confuse Poser (as I've done by hacking obj files by hand) if the vertex normals are specified in the obj file, but have the opposite sign to the normal indicated by the face winding order. If they both exist, they both need to agree.



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