algorithmic modeling for Rhino
After reading “Sculpt and detail realistic rocks” from 3DArtist n°91 (February 2016 ?) here is an attempt to replicate the beginning.
First I began with a sphere mesh with a script which generates a sphere with the maximum number of triangles but not much than a defined threshold.
I scaled that mesh just to fit Rhino grid, but it is not mandatory. What is useful, is to scale not uniformly the mesh (Scale NU). It could be done after cellular modifier applied or before or before and after. The 3 options are possible in the script. If you don’t need them just put 1 in scale sliders.
Ellipsoid mesh is the populated with points, I put 2 independents populations to randomize a bit further. For each vertices of the mesh the closest distance from the populated points is calculated.
Here is an illustration in color of this distance.
This distance is then used to calculate a bump. If domain for bump is beginning with negatives values to 0, it carves the mesh. Instead it bumps/inflates it.
Some images to illustrate the difference with populating 100 points with one or two populations.
Here some images to illustrate the application of scale before carving or after.
Next phase apply noise. At the moment I don't find it good.
Here is a new example, it looks like Cranal texture from Cinema4d,
it used 3D noise, simplex noise and Perlin noise
As these model outputs values between -1 to 1, I apply first and absolute fonction followed by a lower truncation and a rescaling. A graph mapper is also used after the rescaling. After that each vertex of the mesh is translated (bump map). Et voilà !
here a version in 3d in a box
A faster version than the previous one