May 30, 2009
Most object transforms in 3d software are matrices’ heres a rough breakdown of what they are.
A matrix in 3d is an axis defined by three vectors: X,Y and Z and fourth being it’s positional offset from an origin. The length of each axis from the origin defines the scale of that axis; 1.0 being 100%. The ‘identity’ matrix is an objects base transform e.g.
matrix3 [1,0,0] [0,1,0] [0,0,1] [0,0,0] – for the X, Y, Z axis’ and the positional offset from the origin.
So for instance if we wanted to scale an object by 200% along its X axis our matrix transform would look like this – matrix3 [2,0,0] [0,1,0] [0,0,1] [0,0,0]
Notice also that each axis is perpendicular to each other axis (90 degrees) – this is important is if it wasnt we would get skewing. Now each axis’ can point in any direction as long as the other two are perpendicular to it.