That is exactly what I decided to do, which means a great deal of complex shading networks. Redhsift was required for this renderer, so I did have limits on the depth of the shading network.

When working with TriPlanars, UVs are not being used anyways, so I only used UVs on specific areas instead of the complete model.

Pilou, Zbrush can handle 50m polys no problem I am sure...but this was an optimized export from Moi so the topology was useless for sculpting or vertex painting. If I used settings that Zbrush would need, then the asset would easily be 1 billion polys. Working with such dense assets needs a proper pipeline which I didnt have the time to setup. The challenge is working with a 1500 meter asset that gets viewed up close with a 6k render! I never worked on such a huge asset before, and I would never be able to do it without using Moi on 95% of the asset.

Thats why I found 3d coat interesting because it can take the UVs from Moi and do a layout on import.