Hello all,

So I've had this happen frequently since I started character rigging in Houdini a few months ago, and usually if I mess around enough it just goes away on its own, but now I need to get to the bottom of it.

So I'll have keyframes on some rigging elements (IK goals for instance), and in the animation editor and on the object's parameter values everything looks as it should. However, what I will see in the viewport is, for example, one IK goal at a particular keyframe just snap to some position far away from where it should be. Often times it is just for one frame, and will snap back to the right place on the next frame. It seems like this is a bug, because you can only notice this in the viewport - the translate values on this goal at this frame are correct.

I don't know why this happens. It often seems to happen when I move keyframes around though. In this case I noticed it after applying chops to my keyframes.

Anyone encounter this or have any ideas?

You may need to enable only integer frames. Locate in the timeline setup button in lower right corner of UI.

Integer frames are already enabled.

I can recall something like this also happened to me before.. but I cannot remember how I fixed it. (Or it may totally be unrelated)

Probably something to do with the sampling of the CHOPs curve?
Or maybe you need to check the tangent/bezier types in the animation editor, see if one segment type flows well to a different connecting segment type?

Thanks galagast, I'll give it a try. Moved onto a different kind of project so might be a few weeks before I have an opportunity to test.

No worries, I wasn't really even sure if my answer would help.
Best of luck!

Hi mbbuckley,

there are a few things that could be at the root of it. Sometimes CHOPs are not very explicit about when you've created some kind of dependency loop, but also having ‘Time Slice’ enabled on chop nodes prevents being able to scrub backwards in the timeline, and would quite possibly cause similar issues on moving keys around, so maybe worth checking for any of those (it lives under the ‘Common’ tab in a chop nodes parms).

It's hard to say any more about these kinds of problems without seeing the scene in question

Cheers,

Henry

Thank you Henry. I had all the ‘time slices’ not enabled, so I suppose it isn't that, although I have noticed that back scrubbing the time line can seem to trigger the snapping over that time range. It seems that one way to fix the problem is by scrolling to the beginning of the time range, hammering the the ‘unload’ parameter on the common tab of my outputting chop, and then playing through. Not exactly sure what this is doing, but after letting the animation playthrough it appears I can then scrub freely through the frame range and avoid the shaking and snapping.

I have also made sure that all my chops are using the exact same sample rate of 24 frames per second (which is also the playback rate).

Heres a video of the type of thing I'm seeing:

Welp, I think I solved it. Turns out I had a blend on my left arm's IK_Solver not set to 1, which caused issues for me. Nice to have the other arm to compare to.