Encouraged by this thread:
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=8373&highlight= [sidefx.com]

I try to ask one of my all-time-favorite questions:

If I want to use quaternions in expressions:
Do I need to use matrix values instead?

Background:

I want to sum up quaternion rotations and extract XYZ and the angle to use them in transformAxisSOP.

Georg

The expression language lacks any real tools for dealing with quaternions. You can always write your own custom expressions but this can be a pain. VEX has better support for quaternions so you could always do your math there then fetch the result using the point() expression.

As my math needs recursive access to all previous frames I am not sure I can handle this.

But basically you suggest I import the parts I need to calculate my quaternion as parameters into a vex SOP calculate some quaternion and set the result as a point attribute?