Procedural rocks carved in Houdini.
The main idea is to use boolean operations in intersection mode. I use it 2 or 3 times.
Since vdb combine overall works more stable than polygonal boolean sop I tend to use it more, especially on detailed shapes.
Starting with simple shapes like box or tube with low collumn amount I create base rock samples, about 5-6 items. Trying to give it a detailed look already in this early stage, because later it will be computationally harder to do. Then I scatter them on points. Here I use attribute randomizer node on points for randomizing attributes like pscale, orient, scale. Also I create random attribute for to be used in switch sop to choose different rock sample per point from those which were pregenerated before. Point cloud can be generated either with isooffset+scatter sops or add+pointreplicator depending on the final shape you are looking for.
I try to use attribute vop for noises as much as I can. Noises I'm using are anti-aliased, turbulence, voronoy f1-f2, manhattan, chuybyshev.
Also I use foreach sops often.
I'll try to do short breakdowns soon.
Textures are made in Maya with procedural Redshift noises.
Thanks for the interest and watching!