Assimp can be a real pain to use with skeletal information.

Therefore, I wrote a simple utility that loads a file with Assimp, uses Lemon Graph Library (https://lemon.cs.elte.hu/trac/lemon) to parse it, and exports the info to ozz-animation's own binary format. Furthermore, it uses Cereral to create a JSON of the model for your game engine, all neatly bundled up and ready to use.

To build the example (*nix):

git clone --recursive https://www.github.com/ColinGilbert/ozz-assimp-loader &&
cd ozz-assimp-loader &&
mkdir build &&
cmake ..
&& make

To run the Assimp to ozz importer, run:

./model_importer CesiumMan.gltf

It creates a directory called "output" in its local directory and spits out all necessary files.

Enjoy!