Generator for tree types of rocks with detail level:
Poly cylinder based:
parameters for standart polyCube cration
partial offset, rotate scale - cylinder camber
(levels = 2):

Poly cube based:
parameters for standart polyCube cration.
(levels = 2):

GeoShpere based:
radius - geoshpere radius
type - 1-tera, 2-octa, 3-icosa
base frequency - geoshpere frequency
(levels = 2):

Deformation:
levels - detalization parameter
soft edge - angle to make edges smooth.
Its beter to test other papameters by yourself to get to know their meaning.

Rocks inherit UVs from base primitives and can transform them randomly.

You can point maya meterial or slim appearance, which new rocks will have.

Generator can save parameters to file, located in "%MAYA_APP_DIR%/rockgenerator/presetName.rg". A menu "base params -> load -> ..." scans all "*.rg" files in this directory and create menuitems with their names to load them.
And also it has presets for base params: "cylinders", "spheres" and "boxes" ("base params -> presets -> ...").