Graphics, Imaging, and Games Lab

Tree models are widely needed in 3D movies, games, and artistic presentations. Their styles
abound. Due to the complexity and the variety of trees, realistic tree modeling remains a
challenge. For automated methods, the objectives of speed and controllability are elusive.
Data-driven and manual approaches have their own drawbacks: it is inconvenient to obtain
laser scans or photographs of a desired tree, and human intervention can be costly. Another
different style of trees, abstract trees, possesses stylized branches and aesthetic patterns.
However, abstract tree modeling with an emphasis on branching structures receives less attention.
Abstract trees in the art style of Gustav Klimt has never been explored in computer
graphics.

In this thesis we provide procedural methods in two regimes – realistic tree modeling
and abstract tree modeling. For realistic tree modeling, our work is based on the idea of
using least-cost paths – in a weighted graph the least-cost paths between selected endpoints
and a root point form a tree structure. Through the sophisticated design of graph creation,
endpoint placement, and the setting of edge weights, our tree modeling system is capable
of generating a wide range of realistic tree models. For abstract tree modeling, we propose
magnetic curves, a particle tracing method to create stylized trees in the art style of Gustav
Klimt. The method is also versatile to create many aesthetic forms with curves. Overall,
this thesis contributes effective procedural tree modeling methods, and the resulting highquality
results can be used in many computer graphics applications.