Hello

Good luck for your project. The Javascript source code of Three.js lacks of comments, its Typescript source code is a little bit better commented. The stability of its features isn't homogeneous, some loaders are a bit clunky, for example its Collada loader. I'm sure that some existing Java frameworks and engines have more reliable loaders for STL and OBJ. I hope that you'll succeed in supporting much more formats because Wavefront OBJ is very rudimentary whereas Three.js is known to support GLTF which is a lot more capable.