CSG/transform help for defining polygons

I have an editor that converts street plans into polygons. My problem is I do not know how to correctly define the polygons in CSG format(intersecting planes) used by .MAP files. I would like to have someone spell out the forumlas necessary for doing this. I will know the corners of the polygon in world cooridinates. -Or- if you can successfully identify and provide the formulas necessary to derive the Transform matrix shown below you'll win the bid...This transform changes with the shape of the brush but I do not know exactly what kind it is. Vec3d 680.000000 180.000000 -280.000000 Vec3d 680.000000 180.000000 280.000000 Vec3d -680.000000 180.000000 280.000000 Vec3d -680.000000 180.000000 -280.000000 Transform 1.000000 0.000000 0.000000 0.000000 0.000000 1.000000 0.000000 -1.000000 0.000000 0.000000 0.000000 0.000000 Pos 0.000000 0.000000 0.000000 Let me know if you need more info... I don't need code just a good explanation. ## Deliverables Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. Complete copyrights to all work purchased.