Materials and lighting challenge: Nelson flying saucer large pendant

[GeneDavis]

I got this from the 3D Warehouse, and modified the model to add the ribs and segment out the materials so Chief could be used to assign them properly.

 

I cannot seem to get the right combination of materials, emissivity and translucency, plus light types, strengths, and position to get a realistic render.  Plus, and this is big, CPU raytrace and PBR deliver very different looks.

 

What can you do to guide me.

Nelson saucer.plan