TreeCreation 

A program for creating and simplifying realistic trees

 

Project start: October 1999 
Funding: no money for this qualified work...
Authors: Gregor Lehninger, Christian Petzer
Contact: Michael Wimmer  

Description
 Creation of very realistic trees using more than 75 parameters and random values.
Application
 Users can generate sets of geometric trees for urban visualization, architectural planning, virtual environments. 
Problems

Rendering speed

Creating realistic trees causes a very large number of triangles (40.000 - 400.000). Our goal is to reduce the number of triangles to about 1.000 by keeping up a high quality.

Approach

Creating 3d model

Trunc and branches are built of cylindrical and textured segments. The angles between these segments, their lengths, their number and some other parameters can be specified in treedefinition files.

Leaves are made of textured triangles or textured rectangles with alpha blending.

Reducing triangles

The first way of simplifying is realized by reducing the number of drawn leaves and reducing the number of branches depending on their radius.

The second way of simplifying allows to precalculate textures of different sides of a tree and to project them on crossed rectangles. 

Publications
 Calculations are based on the publication Jason Weber and Joseph Penn: "Creation and Rendering of Realistic Trees", SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pp. 119-128, Addison Wesley, August 1995

See a detailed description of the most common tree-parameters.