frame interpolation problem


i’m getting an odd result in Motionbuilder 2016

i’m hand animating a character with a standing pause… the two key frames (full body) that create the pause are all linear but i’m still getting sway.

is there a way around this, maybe it’s a typical problem.



Can you post a short video showing the kind of sway you get?
Only thing i can think of is that there can be some keys maybe if you use the control rig, on some of the fk joints.

Try plotting all and see what keys you get and where they appear (if they do).


I assume the flat keyframes you set are fullbody keys too. If yes, then im not sure what can cause that :flushed:


yes. full body keys. i’m not sure i can easily post a vid… but maybe i can describe it better.

so there aren’t any extra key frames in there. but i am using aux effectors on the hands. they don’t have key frames either, but maybe the extra influence on the rig is weirding it out?

is the typical method, to avoid sway, to just interpolate segments of the curves as linear?


I had the same problem and reported to autodesk, they confirmed it as a bug and are working on it. The solution for now is to use the button Flat key. :shrug:


yes. i got the same response. thanks for confirming that.

although i wasn’t sure exactly how to apply it.

do you select the keys to flatten then hit flat or just the “lead in” keyframe (as you would to make it linear, stepped, etc…? it seems to insert a key frame in there.


The flat button is indeed to create a flat keyframe at that time, so you have to go to the lead in keyframe and hit flat, then go to the lead out and hit flat again. It also working by copy/paste the first flat keyframe to the last. Remember to go to selection or body part to avoid creating a flat keyframe for the whole body.


Thanks! i wondered how that actually worked.