I've heard people say that if we want to export the tracking data from AfterEffects to Maya, for example, we need to fill the affected layer with solid white color and then create a black solid beneath that layer which has been filled with white.
After that, do I just select both layers and Pre-Compose them?
That's all? I think there's something that lets you choose "Alpha matte" and "Luma matte" from a drop-down box, but I dunno how to do that part.
If you're trying to generate a grayscale matte for a single layer, you can simply solo the layer in its comp, add the comp to the render queue, and use the "Alpha Only" Output Module.
Alternately, you could apply the "Fill" effect to the layer, change the fill color to white, add a black solid behind it, and render normally.
This will give you a matte, not tracking data, though. You may be able to do a 2D track on the matte, but by generating a grayscale matte, you're throwing out a lot of data that could be useful to a point tracker.
If you want to get 3D motion out of AE and into Maya, try the MoCon scripts at 3dmation [link]. (I'm a C4D user, not a Maya user, so I won't be able to offer much help beyond that.)
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