Posted by B. Douglas Ward on March 27, 2001 at 14:10:23:
In Reply to: Matrix file posted by Phoebe on March 27, 2001 at 10:43:47:
Phoebe:
This is really a "Bob" question, but I'll take a shot at it.
The format you are using is wrong. Program 3drotate expects a 3x3 orthogonal
rotation matrix next to a 3x1 translation vector. So, it expects the
input to be 3 rows by 4 columns. What you have is 4 rows by 4 columns.
Sidebar: Some graphics programs use a single 4x4 matrix to represent the
above rotation and translation. The advantage of this is that a single matrix
multiplication takes the place of a matrix multiplication followed by a vector
addition. In such cases, the final row of the matrix appears as the one that
you have provided (i.e., 0 0 0 1).
So, the solution would be to simply eliminate the final row of your matrix.
Unfortunately, this won't work either, since the given rotation matrix is
not orthogonal, as required by 3drotate.
Doug Ward