(2020-03-02, 1:47)Orion Pobursky Wrote: Unfortunately I think you'd get better luck in a Blender focused forum or a larger AFOL community forum.
Hello, I am the Mecabricks guy
If you want to get in touch with me, I could answer your Blender questions I saw in this thread. However, I can already tell you that if you want to get photorealistic results, you will have to write your own addon for Blender in order to build your specialised materials for the built in renderers (Cycles/Eevee). Generic formats like collada can only output generic materials. In the case of Blender, it is basically the principled shader with default settings. Besides as you already found out, you do not have a great control over how material and mesh data are structured which has a great impact on the render time and memory used.