Smart bone points "vibrate"? Annoying issue

[heyvern]

Going a bit insane. working on huge short deadline project. Ran into annoying issue with smart bones.

I create a leg/knee smartbone for the calf of a leg. It looks fine in the action, but when I rotate the bone in the timeline the points moved in the action "vibrate" and "wiggle" sort of popping their curve handles or curves. The main center point is peaked in the action there are other points involved. It's quite frustrating that it works and looks perfect in the action timeline but not when using it in the the main timeline.

[synthsin75]

First thing I'd check is that the smart action has enough frames to interpolate over. Very basic, so not likely your problem.
Second thing I would check is if those points have been inadvertently keyframed in any other smart bone action, as that could conflict.

Barring those two, my best guess would be maybe points too close together (or moved too close by the smart action)... where their curvature could be getting exaggerated.

[heyvern]

yes almost certain it’s the two action conflict. some of the points moved in one action are moved in another action. i basically have redone this with simpler rigging. i’ve had this happen before but it’s rare and but couldn’t remember how i fixed in the past.

[Greenlaw]

If there's a conflict between two Smart Bones, check out the Mix Smart Bone technique described here...

Mixed Smart Bones in Moho(ENG subtitles)

It's very clever, and it's saved me a few times over the years.

There's even a script that will do the basic setup for you...

Mix Smartbones Script for Moho12 (ENG subtitles)

...but I highly recommend learning how the technique works first so you can modify the script's result or troubleshoot any errors.