Madaxe

I have a series of 3d points in space they are on an arbitrary plane but i want to move them to a plane AX+BY+CZ+D=0 A=0, B=0, C=1, D=0 so the XY Plane.the matrices for this is identity.From the points i assume 0) All vectors will be unitized1) the first point in the polygon will be moved to 0,0,02) the first and second point in the polygon will define the vector for the X Axis3) the first point and the last point in the polygon will define a construction vector4) the cross product of the X Axis Vector and the construction vector will define the Z Axis vector5) the cross product of the X Axis Vector and the Z Axis Vector will define the Y Axis Vector6) using the three vectors and the origin point construct a matrices7) invert the matrices Multiply each polygon point by the inverse matrix to transform them to the xy planeDoes not work the polygon is moved but not rotated correctly what do i need to do?All help is appreciatedThanksMadaxe