[TrevorJ]

There's a lot of optimization that needs done for realtime.

For any given asset you may have a pipeline like so:

Sculpt hi rez model in Z brush > create low rez model and retopologize (can be a very manual process) > UV unwrap and bake the high rez details down to Normal maps for the low rez mesh > Use DDO or Substance painter to create custom textures for diffuse, metalness, etc > Rig model (if you are animating it) Then export to the engine. Rinse and repeat based on major art changes.