Trees is an ongoing project written in openFrameworks, which simulates tree growth influenced by sun and gravity and creates 3d printable models from these simulations.
The project's source code can be found on github:

Figure 1: Interface of the simulation

Figure 2: Calculations of Light beams

Figure 3: Tree 1

Figure 4: Tree 2

Figure 5: Tree 3

Figure 6: Tree 4

Figure 7: Tree 5

Created in collaboration with Erich Grunewald