The Cave – Rocks
I created an “alphabet” set of modular grey rocks to be used all over the game. Simple rock shapes were sculpted, polypainted in a dry-brush style just to highlight the edges and decimated (if we needed LODs we would just decimate out various resolutions) in Zbrush. Diffuse, normal and AO maps were extracted using XNormal. The modular pieces were mostly grey because they are versatile to be used in all lighting situations.
To create more unique versions (like a sandstone), the baked out maps would just be painted/color adjusted in Photoshop.
The sculpted rocks were then used in the Zbrush canvas to create tileable rock meshes that come with custom tileable maps. Multiple tiles would be used to create big patches of background rock geometry. This method is very versatile especially when combined with the lattice tool in Maya to warp and bend the geometry further. The effect is particularly great if you then sprinkle in fully sculpted rocks of the same type to break up the geometry.
The sketch test was made in about 15min, given an already existing sculpted (and messily polypainted!) rock.
Some more in game examples of the assembled rocks in game: