02/02/10 16:11 .net
>>455
What I meant is that a "orthonormal" 3x3 matrix represents pure rotation.
If a 3x3 matrix contains scaling or shearing, that matrix is NOT orthonormal.
In this case, you must calculate the inverse of the transpose of the 3x3 matrix,
instead of just using the original matrix, in order to transform "normal" vectors.
However, you said in your previous post (I assume 437 = 455) that you wanted to
transform "direction" vectors. Unlike normals, direction vectors can be transformed
simply by using the upper-left 3x3 submatrix of the original 4x4 transform matrix.
I'm very sorry to have mixed up "direction" with "normal."