Entry point: ModelLoaderRegistry
loader interface: ICustomModelLoader
custom model: IModel
ModelLoader is responsible for splicing into vanilla model system.
(you probably don't need to use it directly)
Interop with vanilla models isn't great yet
(vanilla models can't refer to custom ones as parents), will improve in
the future.
Includes loader for B3D models, with animation support
(net.minecraftforge.client.model.b3d).
Blender export plugin with compatible coordinate system:
https://github.com/RainWarrior/B3DExport
OBJ loader is being written, will be included at some point in the
future. For now you can convert OBJ to B3D via blender, or wait.