Export GLTF containing only animation data

Questions
1

Hello everyone!

Is it possible to use the threejs GLTFExporter to export a GLTF containing only the buffers for animation data, no other buffers?

This tutorial shows a way to load a GLTF with these restrictions on top of a base GLTF that contains the other buffers. What I want to do is the inverse: export a GLTF containing only animation data.

More precisely what I want to do is send animation data created on a client to a server where it is integrated in to a common GLTF file. I know I could just send the node references and raw animation data, but I think sending valid GLTFs would be kind of neat.

I read the source code and it doesn’t seem to be possible except for removing parts from the exported GLTF after the export is complete, which would involve a lot of processing overhead. Am I missing something?

Thank you so much for this amazing library and in advance for any words of advice!

2

What will happen if before exporting you make all objects invisible and set the GLTRExporter opiton onlyVisible to true?

3

Thank you so much for your answer, that did get me significantly closer to what I was aiming for.

My error so far was that I simply set scene.visible = false, which didn’t have the desired effect. It required scene.traverse((object) => (object.visible = false)) to actually accept that it shouldn’t include the other buffers.

However, it seems that the exported GLTF loses its channels -> target -> node references, because the GLTF lacks nodes. In the tutorial linked above it seems that the whole node structure is generated for the GLTF, but the buffers are omitted. I believe that is why the animations can be applied to the base model so easily.

Is there a way to tell the exporter which types of data to include?

4

It is impossible to export skinning animation to glTF, without also including a skeleton. The resulting file would not be valid. I think you could perhaps replace the SkinnedMesh’s geometry with a single triangle or something trivial like that, which should allow the file to be exported correctly.

4 Likes
5

Maybe the only way is to modify GLTFExporter.js. There are separate functions for the different data, e.g. individual animation clips are processed by processAnimation. But, honestly, I doubt it is worth going this way.