Comment by s-macke
9 years ago
The simplest techniques for 3D rendering without relying on a GPU and WebGL are indeed (2.5D) raycasting engines (such as this Voxel Space engine). A short google search reveals for example:
http://www.playfuljs.com/a-first-person-engine-in-265-lines/
Also read the readme file of this Voxel Space engine. Maybe this is already enough to understand the principle.
Loading .obj files is pretty easy, and basic triangle rasterization isn't too hard either. Still probably a bit harder than height maps.