I've been playing around with a trial of Groboto
www.groboto.com This is an unusual modelling tool that lets you build objects by combining primitive shapes with Boolian operations; nothing unusual there but the primitive shapes are stored and combined as procedural surfaces while you work. At any point your creation can be converted into a polygonal mesh which is built starting from the intersection edges so you always get a clean result, anyone who has used Boolian operations in general modellers where two mesh objects are combined will know how messy the intersections often are. Another advantage is that if you decide to make a change this is done with the primitive objects and the poly mesh is then rebuilt so a change to even the most complex object is quick and easy.
Before the trial period expired I made a couple of relatively simple, in Groboto terms, objects although the meshes they export as would be non-trivial for a traditional modeller. One of these was this "Mushroom" rock formation. Which I used as the main element in this scene. The Groboto mesh is smooth and continuous so takes displacements well, raytrace Objects was off for this render. The rock stack surface is quite basic but I was really just testing to see how well the meshes experted from Groboto worked. I added the Executive Yacht, a freebee from TurboSquid, to give the scene scale.