okay i have figured that the thing to really learn is D3D. but the one thing no one mention is open gl has very good nurbs support like used in quake 3 what about d3d?

Opengl does support NURBs, although I seriously doubt they used it in Quake. My guess is they make use of their own specialized, highly optimized curve subdivision code. As for Direct3D supporting curved surfaces--no. You''d have to do it by yourself.