Perfect, thanks. I'll write an editor script that remembers the initial pose and will apply itself before play, or something like that, since scrubbing in the timeline in edit mode does alter the pose. That way there won't be any issues. I know FinalIK does something similar (and I had to write my own system for that as well to get it working with timeline properly in edit mode without breaking play mode ... so this makes sense). I still don't understand why some models work fine when scrubbed in the timeline while others dont, but maybe its just the luck of the draw regarding how the pose is changed. If you haven't, can you add a line about this in your documentation about use with timeline? It took me a whole day of work to figure out that's what was going wrong ... at first I thought the data just corrupted so I played with git reverts. If its already there, I just didn't notice it, so oops. Anyway, thanks so much.