[ODE] Understanding Rotation Matrix

[Joey Coyle]

Hi,

I am new to ODE, and new to Matrices, and 3D

I have looked through the documentation, and I can't figure out the 
layout of the rotation matrix.

These functions set and get the position, rotation, linear and angular 
velocity of the body. After setting a group of bodies, the outcome of 
the simulation is undefined if the new configuration is inconsistent 
with the joints/constraints that are present. When getting, the 
returned values are pointers to internal data structures, so the 
vectors are valid until any changes are made to the rigid body system 
structure. Hmmm. dBodyGetRotation returns a 4x3 rotation matrix.

How is this rotation matrix laid out?

On the web, I find a rotation matrix looks like this

R11    R12   R13
R21   R22    R23
R31   R32   R33


where Row 1 is Right,
Row2 is Up
Row3 is Out.

Why is ODE returning a 4x3 matrix?   And how is the array laid out??????

thanks,
joey