I'm making a WebGPU renderer with WebGL fallbacks, with a path tracer for 'photo mode', specifically targeting agents writing web 3D things. I'm not especially far into it though. It doesn't use 3D models; there's a DSL for making things.

There's a demo app here that only works on desktop - https://fab.ooer.com/ (scroll down in the right hand menu to quality and change to 'trace' for photo mode)