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kcoley / gltf2usd

command-line utility for converting glTF 2.0 models to USD
MIT License
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Different Animation Interpolations and Funky Results #115

Open enzyme69 opened 5 years ago

enzyme69 commented 5 years ago

Got this example from DonMcCurry: 4 types of interpolations: Archive.zip

When converted to USDZ: raggedneararabianhorse-max-1mb

Surprisingly Stepped Keys works!

Error message: cubic spline interpolation not yet implemented! Defaulting to linear for now...

There are few animations where up-down become left-right.

I think this is worth looking into.

enzyme69 commented 5 years ago

Actually "stepped keys" is still not exactly stepped in USDZ. But as GLTF, it is really stepped. Maybe keying visibility is still not possible. I want to have 3D animation that works like GIF.

kcoley commented 5 years ago

@enzyme69 I think the issue is because the source glTF file is using cubic spline interpolation, but that is not supported in usdz. Technically, it only supports linear animation. I bake the animation to support stepped animations, though I would have to add some additional logic to try baking cubic spline animations. Though, since usdz is using linear animation, there may be some "jumping" behavior based on the frame rate set since this is kind of a workaround.

I'll make a separate issue to bake out cubic spline animations.