Order of transformation for model registration

Hello everyone,

I cant seem to find a definitive answer on this. I’m using ALPACA through Slicermorph to register 2 models to eachother. My question is regarding the resulting transformation. Is there and order of translation and rotation ALPACA uses, or is this irrelevant?

Thank you kindly.

To elaborate. within the single transformation that happens for alpaca, does it matter if the order is XYZ, or ZYX, or any other combination.

I know that with multiple transformation rotations the rotation order matters, but is this also within a single transformation like you get from model registration?

Euler angles is a very poor representation of orientation (gimbal lock issue, many variants in axis ordering, no 1-to-1 mapping between angle values and orientation, etc.), therefore we avoid this parametrization.

Probably Alpaca uses a simple 4x4 homogeneous transformation matrix representation for 3D translation and rotation.