SpeedTree is a hybrid 3D modeler and runtime
engine that helps developers integrate great-looking trees in
real-time applications quickly. The focus is not so much on
best-possible quality, but in keeping a balance between quality and
Tree handling is divided into two different subtasks. First, you generate realistic tree models using an editing tool. Second, you apply proprietary algorithms to render the trees efficiently. This approach is interesting, and attacks the core of the problem: As tree geometry is inherently complex, and sometimes the tree will be seen far away, it's very hard to handle the problem with a modeling-only solution. Understanding the modeling and rendering parts fully is essential to get good trees up and running quickly.
The resulting trees are a perfect balance between speed and
quality. Seen up close, the trees are remarkably believable: you
can look up at the treetop when your character is standing directly
below the tree, and the illusion of volume and parallax between the
leaves is properly maintained.
Additionally, as SpeedTree uses billboards to represent distant trees, creating large vistas with forests is a breeze. Some individual trees do look a bit algorithmic and fractal at certain moments, but when placed in a grove or forest, the results are strikingly realistic: you get animated trees with real-time shadows that you can see far away and up close.
Plus, you get the tree editor so you can create new species, via parameters that control things like branching, the amount of leaves, and so on. This helps you create new species so you can build your own, unique trees.
Speedtree Unity is one of the most popular and widely used vegetation editing tools. Few of its best features include the smooth LOD transitions, foliage rendering, instanced painting, hand drawing, trees growing, tuning of the effects of wind, import mesh props and surface modeling.