Anyone experience odd one frame pops when UV tracking/Ext Bicubic keyframing?

Adjust / track UVs to/around an object, copy to verts, and now you have your ext. bicubic to animate your shape around… cool.

I will mysteriously have one frame pops, where the scale of my bicubic jumps and snaps back to its intended shape. No keyframes anywhere at the frame of the “pop”. Incredibly frustrating when you’ve got something looking good and don’t want to start over…

I’m wondering if anyone else has experienced this, as I’m thinking it may be a bug. I may have hit undo to adjust a shape, which I think could have set this off… Seems like it’s behaving very persnickety…

Am I missing something crucial? Any insights appreciated.

I’ve seen some weirdness when using the shape channel, with the interpolation set to bezier. But you can see the problem in the channel area.
Have you checked your camera?
Did everything look ok in the tracker?

Yup, everything looks ok in the tracker, channel looks smooth/ascends normally, no tracked camera, also, no keyframes at the point of interest/screwiness…

Only thing I can think of at the moment, is setting manual points in the tracker’s offset is making the UVs/verts scale wildly, but it still wouldn’t account for a 1 frame pop & then right back to normal…

I’ve tracked and patched a frame for the time being, but yeah… real odd…

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I would duplicate the action, before trying the following.

Are you seeing the issue in the F8 view? If not it’s probably not a UV problem. Maybe the problem is in the Vertices…
When you determine which is messed up, put a keyframe on the frame before and the frame after. Then fix the one that pops manually.

Or pipe it to a downstream action where you can put a correction on it. You might be able to animate the slip, so you can use the last good frame, move it a little, then pick up with the rest that’s good.

Yeah, I’ve already moved ahead with the latter solution.

But yes, the pop is visible in the F8 view… Unfortunate thing is the pop is on the last frame of the sequence, ha… All good.

Thanks for your help!

i just saw what you are talking about today. I can’t articulate how it happened so hard to re create but definitely happened a few times today and was very irritating.

Be careful with ext bic’s. Before I touch them I always set unaltered key frames, first and last frames. Then I delete them when ready to animate.
Extended Bicubics have had bugs since their introduction, then no one cleaned it up.