I’m writing an automatic impostor generator. You fit a box, or other mesh object, around the objects to be impostored, run my “Impostor Maker” add on, and you get an impostor. The source objects are rendered in ortho mode looking straight at each face. Those textures are composited into a big image. UVs are constructed to map the texture onto the target object. Intended use is low-LOD models for Second Life, which are usually terrible.
All that works. See screenshot below. On the left, a 3D model with 3163 triangles. On the right, an impostor with 12 triangles. The one thing I can’t do yet is create UVs where none existed. I have to unwrap from the UI first to create the UV arrays so I can overwrite them. Does anyone know how to do that?
Previous discussion in 2016. Result of discussion - nobody found the answer, although many things were tried.