I implemented the chain rendering in my Minecraft mod.

Originally I thought I would focus on the chain behavior but rendering seemed more interesting to do.

I referenced the vanilla chain model and leash rendering code and came up with this. It might need some tweaks later (like reducing the scale) but it’s good enough now.

It took me a lot of time to correctly calculate the UVs and vertex positions.
Also internally I opted on using Fabric’s Data Attachment API instead of trying to mixin into vanilla leash classes and it turned out to be a lot easier than I thought. It even handles client sync and saving!