Merging multiple FBX files into a single gltf

Question

I have about 10 FBX files. Each file has a single mesh, skeleton and animation. The mesh and skeleton are the same for all files but each has a different animation.

My software can only handle gltf files so I am trying to convert from FBX to gltf.

What I want to do is grab the T pose model and fill in the geometry (i.e. vertex, normal, uv...) buffers with the T pose, fill the weight buffers with a single skeleton and then define multiple sets of animation matrices, initialized to the values in the FBX files.

I have tried doing this in blender but honestly I have very little experience with the tool as I am not an artist, just a programmer.

For example when I import the 2 models into blender I see this:

Those are 2 models each with their own animation. Since they have the same mesh and skeleton it should be trivial to just copy the animation of the second one and append it to the set of animaitons in the first one. But IDK how to achieve this.

Alternatively if there is a terminal tool or any other mechanism to do this I am fine with it. All I need is to merge the FBX files through any means as I am not going to be editing them.

Based on the most upvoted I manage to get to a state where I can cycle through all the animations in blender:

However when i export to gltf only one animation is available:

I am using this website to check my files:

https://gltf-viewer.donmccurdy.com/

Answer 1

In blender it's fairly easy. If you have two identical armatures, and a certain animation is only associated with one of them, like so:

You can just go to Dope Sheet -> Action Editor

and, with the second rig selected, choose the animation from the drop-down menu.