>x'=1*x + cosT*x + 0*y + 0*y + 0*z + sinT*z >y'=0*x + 0*x + cosR*y + 1*y + sinR*z + 0*z >z'=0*x + -sinT*x + -sinR*y + 0*y + cosR*z + cosT*z No it wouldn't work. You are applying both rotations to the origional coords and then adding the two results. You need to perform the second rotation to the result of the first. The addition only works with matrixs. --Nate