Modeling trees with crown shape constraints

Tree modeling is not only beneficial to plant research, but is equivalently useful in virtual reality. In this case, the tree crown shape is often more important than topological structure of small branches. Different approaches were developed with different advantages. Tree modeling based on laser scan data or images shows a light contribution to tree growth. Sketch-based or image based approaches have weak 3D shape information from 2D data. Based on tree growth rules, a topiary was synthesized in [Prusinkiewicz et al. 1994] for art uses, where parametric L-systems are used with turtle interpretation. But this is not intuitive for ordinary users, so that colonization algorithm [Runions et al. 2007] and light distribution [Palubicki et al. 2009] had to be employed.