Written by Paul Bourke
July 2020

The following biological looking forms are created by some simple growth rules. The key process is the addition of new spheres (child spheres) placed randomly on the surface of existing spheres (parent spheres) such that there are no intersections. Each iteration (generation) involves a search for possible locations. Once no more child spheres can be placed, the sphere size is reduce for the next iteration of the process. There are the following parameters for the process:

  • The maximum number of iterations (generations).

  • The factor by which to reduce the radius of the spheres at the start of each iteration. That is, the child spheres will have a radius that is the parent radius multiplied by this factor.

  • When searching for a new location one can look at just the immediate parent sphere, or include the grandparents, and so on.

  • A small factor that expands the radius of the parent sphere the children sphere are placed on. This is a VERY sensitive parameter, typically values of between 1 (placed on the parent sphere) to 1.2 are used.

spheres 50 0.895 1

spheres 100 0.95 1.11

spheres 40 0.9 1.03

spheres 14 0.7 1