Clasping Trees - A Pipeline for Interactive Procedural Tree Generation

Abstract

Trees in computer games are important components of an immersive game world. Realistic trees adapt to the environment in terms of shape and growth. Manually adapting each tree to its immediate environment is time-consuming. Hence, we present a pipeline to procedurally generate trees. This pipeline's input consists of tree-parameters and mesh sets. Tree-parameters have a direct influence on the final appearance of the tree. Meshes are used to indicate the space of the tree crown and surface for roots. We provide an overview of the necessary methods for procedural tree generation. Our method allows game developers to integrate the pipeline directly into their game engine, skipping the process of importing and maintaining external 3D-models. We used the Space Colonization Algorithm to generate roots of trees on the surface of a set of meshes. For the crown generation, we use an extended Space Colonization Algorithm called Self Organizing Trees. To receive the combined surface and volume of a set of meshes, we voxelize the individual mesh and compose it into a single voxel grid. We introduce two novel optimization methods to further increase the usability of the generated trees. These optimization methods decrease the necessary triangle count of the final mesh. The resulting trees can be used for real-life applications, such as games.