Light searching

Up to now, position and orientation of every branch was determined by its initial parameters like parent origin and seed, without any consideration of neighbor branches. In real world proximity of neighbor branches matters a lot and it is one of the main driving factors forming a tree crown. In version 1.49 there is introduced a basic light searching model. It considers 3 factors:

• proximity of closest neighbor (heading away from it)
• position of crown center (heading away from it)
• ground layer (heading away from it when close to it)

These factors are controlled through 3 new tropisms introduced to Branch3 component: "crownAwayFromNeighbourTropAngle", "crownAwayFromCenterTropAngle" and "crownAwayFromGroundTropAngle" respectively. Surprisingly even light searching model as simple as this has a significant influence on forming a crown. Consider example on the following 2 images. In both cases we see identical plant topology made of 2 components - a stem with bigger number of side branches spawned under the same angle. Even as simple tree structure as this, that looks extremely artificial like on the left image, can after applying just these 3 tropisms change to believable tree crown shape like on the right image.

The direct benefit is that we are now able to create more natural looking regular tree crowns with less effort.

But there is also indirect benefit: Because branches are now distributed more evenly over the plant volume, we need less amount of branches to represent a compact crown - we save polygons in the final model.