I need to process some polygons in 3D. They are typically loaded from an OFF or STL file. Then I need to do some transformations (rotation, move, resize), I'd like to check whether points are inside the polygon or not, whether polygons overalp, and I'd like to merge several polygons into one. I'd also like to have raw access on points and surface indices.
It seems that there are many libraries for 2D, but it's difficult to find something for 3D. Preferably usable with Python/NumPy.