Hi all, I don't know if this is the right section, but I really need to solve this problem. I've been searching for the correct formula for two days. OK, here's the picture: The global rotation of all objects (rot_x, rot_y, rot_z): red object (0.00, 45.00, 0.00), blue object (45.00, 0.00, 90.00) and green object (30.00, 35.26, 35.26). I need to calculate the local rotation of the objects, so the local rotation of the green object should be (0.00, 45.00, 45.00). I want to be able to rotate objects locally, not globally. Here is one formula, but I don't understand how to use it: Code (Text): [ 1 0 0 ] [ 0 cos(a) sin(a)] = Rx(a) [ 0 -sin(a) cos(a)] [ cos(a) 0 -sin(a)] [ 0 1 0 ] = Ry(a) [ sin(a) 0 cos(a)] [ cos(a) sin(a) 0 ] [-sin(a) cos(a) 0 ] = Rz(a) [ 0 0 1 ] [URL="http://stackoverflow.com/questions/6252223/adding-local-rotation-to-global-rotation"]source[/URL] I hope someone can help me solve this because I'm newbie in math.