Hi. I searched for solution my problem through the Gamedev forums and couldn''t find any needed post. Wouldn''t you like to help me? I have a BIG problem: I need to do triangulation of polygons. These polygons are in 3D space with world coordinates of its vertices. I can simply calculate its normals. For triangulation each polygon I need to draw one rectangle circumrectangle?- rectangle which contain the whole polygon) which lies on the same plane as polygon. Then I have to put some grid points on this rectangle. It is ALL. Triangulator can divide rectangle if he know these points. How to draw this rectangle to make it laying on the same plane that polygon lies (and contain whole polygon)? How to draw these grid points? I would like to use a matrix transformations but don''t know HOW. I would like to have each POLYGON (in iterations) in X-Y plane. Then I''d like to draw points with constant Z-coordinate (i.e. 10). I''d like to check some things like lines intersections, but ALL in this 2D space. After all I''d like to my 2D point have correct coordinates in 3D world. Is it possible to do it with transformations OpenGL matrices? PLEASE HELP ME IF YOU CAN, I need solution as soon as possible. (If I could please). Very Thanks for Help With Best Regards Maciej Jakubowski