public static Matrix getRotationJAMA ( Matrix4d transform ) { Matrix rot = new Matrix ( 3 , 3 ) ; for ( int i = 0 ; i < 3 ; i ++ ) { for ( int j = 0 ; j < 3 ; j ++ ) { rot . set ( j , i , transform . getElement ( i , j ) ) ; // transposed } } return rot ; }
Convert a transformation matrix into a JAMA rotation matrix . Because the JAMA matrix is a pre - multiplication matrix and the Vecmath matrix is a post - multiplication one the rotation matrix is transposed to ensure that the transformation they produce is the same .