Splits

Trees that split into two parts as they grow upward are common in nature. In SpeedTree Branch Generators can add a configurable split to add realism to your tree models.

Note

In older versions of SpeedTree, there was a similar feature called "bifurcation." That term is still used in SpeedTree 8 and later but refers to a generation style. See Bifurcation.

How to split

You'll do your editing for splits between two generators. The starting generator, for example, a trunk, will be the control for whether or not there are splits. The generator that follows (as an extension of the parent) is where the new post-split branches are placed.

A generation hierarchy with a Tree generator, a Trunk generator, and a Split Branches generator. Next to it is a trunk with split branches. The Trunk generator has an arrow pointing to it and is labeled "This generator is where you edit splits." The Split Branches generator also has an arrow pointing to it and is labeled "This generator is where the splits show up in the extended parent." There is an arrow pointing from the Split Branches generator to the first branch in the split on the tree.

Step 1: Click the generation level that will start the split.

Step 2: Edit the Skin:Splits:Chance property to increase the likelihood of a split.

Step 3: In the generator that is splitting, make sure Extend Parent is enabled.

Step 4: Edit the other Splits properties to control the actual split geometry. You can control the thickness of the splitting branches, the balance between them, and the smoothness of the "crease."

UV tiling

Two trees, showing it before and after it has been split. The before tree has the trunk and each branch labeled with numbers 1 through 4. The second tree shows how branches 1 and 2 have been split by labeling the tree with four 1s and two 2s.

When you split a branch, the texture wrapping around it must also split cleanly. This means your U tiling must be divisible by two, so it can accommodate being halved. For example, if your trunk has UVs that tile twice in the U direction, each of the splits will then be able to tile once.

For more information on editing branch UVs, please see the UV Mapping section of the Branch Generator.

Different extensions

In the "Extend Parent" property, there are options to extend one side of the split and not the other. This allows you to have entirely different style branches growing off of either side of the split.