Given a surface normal, the choice for a tangent vector is arbitrary for a flat surface. You have the freedom to decide the direction of the tangent vector. In your case, the tangent vector can be defined from the base point of the normal to any arbitrary point on the polygon, this can be the mid-point of an edge or even can be one of the vertices. The choice is yours. Calculating the bitangent, then, is trivial. It is the result of the cross product between the normal and tangent.
The technique would be: 1. Get the tangent (this is arbitrary - it could be an edge or a vector between the mid-point of edges and the base of the normal etc.- any vector that lies on the surface meaning you just need two points on the surface, does not matter where - this works only for flat surfaces which I assume you already have.) 2. Cross the normal and the tangent to the bitangent. You can find some reference here <https://knowledge.autodesk.com/support/maya-lt/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/MayaLT/files/Appendix-A-Tangent-and-binormal-vectors-htm.html#mtc-english> - Alok -- You received this message because you are subscribed to the Google Groups "Python Programming for Autodesk Maya" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/python_inside_maya/CAPaTLMRDu-S%2B9%2B_tOqHAgAFqR2hQqBSqzHYHKEiJR3-TygEFdg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
