I am working in python, however, it should be consistent with C++ as well, using Incremental mesh, i am unable to get triangulation for the cones as shown in the picture, however, two of these are triangulated. Would appreciate if someone could point me in right direction, apparently, shape healing doesn't seem to fix it. I think something is odd with these faces as reexporting file from another cad software fixes it, but i am unable to figure it out