Thanks for your replies. I figured out how to resolve my issue. Every face is obviously a plane itself, it was required only to specify clockwise order of vertices cause Quake (or NetRadiant) map format requires this order.

Hi all, At first sorry for any possible mistakes, I'm a noob in 3d programming and not a native English speaker. Please help if somebody can. Here is the problem: I have a mesh which is a set of faces, where a face is 3 vertices and a normal. I need to convert the mesh into NetRadiant map file forma...