Principal curvature information have wrong sign

Hello guys!

I tried recently to obtain curvature information for points projected onto a surface (in general I work with BREPs) and I found that the sign of K_1 and K_2 is not always correct. For example, I get for a sphere both K_1 and K_2 negative, while they should be positive. Could anybody, please, tell me whether my approach is correct or there is a bug? In my pipeline I consider, as the input, a BREP and the mesh faces’ centroids (the mesh is a discrete representation of the BREP). (14.6 KB) sphere.3dm (35.9 KB)
sphere-re-1.obj (1.0 MB)