3den is a 3D rendering system for LÖVE 11! It's very much a WIP but I might not get around to finishing it. It's largely a Lua port of another game engine I wrote a few years ago. I made it as a proof of concept, both to explore the new features of LÖVE and prove to myself I still know how to program 3D stuff.
This engine requires the class implementation in class.lua, which I modified from one on the Lua Users wiki.
Don't ask me how the lit shader works. I copied it almost verbatim from my old project and I don't remember how the heck it works.