Mocha Pro splines and crazy animation values in Flame

Im dangerously proficient in Mocha to be able to use it but when something breaks I’m clueless. Mocha Pro splines look fabulous in Mocha. Awesome. But a couple of my splines, when loaded into Gmask Tracer, the Axis data goes absolutely insane and goes off the charts on the X and Y…like, what should be 4000 spikes to 1.25515e+06! 90% of all the keyframes are in fact correct, but, in a few places it spikes so hard and is sadly unusable. Rendered alphas out of Mocha look totally fine.

Rumor on the street is there’s something whacky with drawing Mocha splines clockwise vs counter clockwise?


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For that exact reason I use only the axis in the mocha exported gmask node when there are more adjustment needed in flame.
If you open the gmask in flame you get a crazy amount spline points.

Would love to hear more about the solution for your problem to!

From what I remember, the number of spline points doubles when translating to Flame. It’s because the mask descriptions aren’t identical and the extra points give the roto more similarity.

When in Mocha, I still only use the Xspline and NOT the BSpline because the handles translate accurately.

In a version of Mocha from two years ago, one of the tricks was to make sure the spline was drawn clockwise and not counterclockwise. Not sure if this is still the case, but we used to see errors like yours with reversed vectors.

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Hi there! Mocha product manager here.

Josh is correct: The splines double if you are converting from X-Spline to Bezier splines because of the maths involved in converting between the curve types. Not much we can do about that except ask Autodesk very nicely to support X-Splines. :slight_smile:

The clockwise/counterclockwise thing was fixed a while back (Mocha 3.1 if I recall correctly).

What I suspect is happening is the collapsed transform of planar data and manual keyframes are causing the spike. Sometimes if a planar track is skewed badly, the distortion in the plane can throw off a data export when collapsed to baked keyframes. You don’t see it in the Mocha render because the data is kept separate, although i’m surprised you’re seeing it in the tracer export.

I’m happy to take a look if you can throw me your Mocha project file. I don’t need the footage, just the .mocha file. If you’re in the plugin, you can just export it from the file menu.


I think I had that backward… I use the BSplines and not the XSplines. I was confused. Thanks, Martin!

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