I'm gonna bet that halo is going to say, "Oh yeah, I forgot to mention I'm not doing this in Blitz3D so I can't use TForm." Every other time he's asked this sort of question he forgot to mention that he can't use TForm to do it.
I'm not so hot at 3D math so I can't really help you here, but it sounds like a fairly basic question. I imagine the correct sequence of cross products and/or dot products is already noted down in linear algebra textbooks.
I'm not so hot at 3D math so I can't really help you here, but it sounds like a fairly basic question. I imagine the correct sequence of cross products and/or dot products is already noted down in linear algebra textbooks.