I have a big problem in my master thesis project unsing OpenCascade: I don't know hot to calculate the attribute of a edge (convex or concave).
This is the definiton of my problem:
Input: Two neighbor faces (they share a common edge)
Output: Are convex or concave?
In OpenCascade it is easy to make some reasoning about faces and edges. You can translate a face into a parametric surface (U,V domain), and an edge in to a parametric curve (U domain). I can map the curve with the surface too: U of the curve -> U,V of the surface. I know too the valid range of the U,V of the faces and valid range of U. in the curve. This is an easy task.
With this mapping I can calculate normals N of both faces, and derivate of U, V and the direction of the edge for a given (X,Y,Z) point or (U,V) parameters of one of the faces. The problem is, that I don't have enough information to obtain the attribute, because a pair of normals are always ambiguous. What I am doing wrong? I am looking in internet, and I don't find the method to use.
First thanks for the help... I appreciate very much your time