Physically Guided Animation of Trees

Ralf Habel, Alexander Kusternig, Michael Wimmer
Physically Guided Animation of Trees
Computer Graphics Forum (Proceedings EUROGRAPHICS 2009), 28(2):523-532, March 2009. [draft]

Information

Abstract

This paper presents a new method to animate the interaction of a tree with wind both realistically and in real time. The main idea is to combine statistical observations with physical properties in two major parts of tree animation. First, the interaction of a single branch with the forces applied to it is approximated by a novel efficient two step nonlinear deformation method, allowing arbitrary continuous deformations and circumventing the need to segment a branch to model its deformation behavior. Second, the interaction of wind with the dynamic system representing a tree is statistically modeled. By precomputing the response function of branches to turbulent wind in frequency space, the motion of a branch can be synthesized efficiently by sampling a 2D motion texture.

Using a hierarchical form of vertex displacement, both methods can be combined in a single vertex shader, fully leveraging the power of modern GPUs to realistically animate thousands of branches and ten thousands of leaves at practically no cost.

Additional Files and Images

Additional images and videos

Image: Animated Tree

Additional files

draft: Physically Guided Animation of Trees
Video: Video

Weblinks

BibTeX

@article{Habel_09_PGT,
  title =      "Physically Guided Animation of Trees",
  author =     "Ralf Habel and Alexander Kusternig and Michael Wimmer",
  year =       "2009",
  abstract =   "This paper presents a new method to animate the interaction
               of a tree with wind both realistically and in real time. The
               main idea is to combine statistical observations with
               physical properties in two major parts of tree animation.
               First, the interaction of a single branch with the forces
               applied to it is approximated by a novel efficient two step
               nonlinear deformation method, allowing arbitrary continuous
               deformations and circumventing the need to segment a branch
               to model its deformation behavior. Second, the interaction
               of wind with the dynamic system representing a tree is
               statistically modeled. By precomputing the response function
               of branches to turbulent wind in frequency space, the motion
               of a branch can be synthesized efficiently by sampling a 2D
               motion texture.  Using a hierarchical form of vertex
               displacement, both methods can be combined in a single
               vertex shader, fully leveraging the power of modern GPUs to
               realistically animate thousands of branches and ten
               thousands of leaves at practically no cost.",
  month =      mar,
  issn =       "0167-7055",
  journal =    "Computer Graphics Forum (Proceedings EUROGRAPHICS 2009)",
  number =     "2",
  volume =     "28",
  pages =      "523--532",
  keywords =   "Animation, Physically Guided animation, Vegetation, Trees",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2009/Habel_09_PGT/",
}