Stewer, thanks for assuming a comma in the appropriate place in my statement to render it correct :-). I was actually referring to references I had seen implying that quaternions calculated for a specific frame of reference cannot be meaningfully applied to another, unrelated FoR without receiving invalid results. On the human joint issue, I'd bet that quaternions are what CL uses for Inverse Kinematic calculations, hence the sometimes unnatural and unpredictable joint strangeness seen when pushing IK to its limits. (Well I know MY knees don't bend that way...) Pity IK uses seems to ignore joint rotation limits when engaged.

---

My ShareCG Stuff

Verbosity: Profusely promulgating Graham's number epics of complete and utter verbiage by the metric monkey barrel.