Can new geometry be generated by Blender shader?

Is there a material node-based way to duplicate the faces of the model, like in this picture: https://i.gyazo.com/ec920106b598710ab4cf4dae2b7df810.png Some effects I use need such multi-layer “sandwitch”, and I think it would be more performant to generate it from a shader, since the mesh might have Armature or other deformation modifiers.

not really !

but you can use modifiers or particles system to add geometry
or even the dupli verts face ect.

happy bl

Thats unfortunate, but thanks for confirmation.