Large Steps in GPU-based Deformable Bodies Simulation*


Eduardo Tejada[1]
  Description    
Physical-based animation of deformable objects has gained considerable attention in the last two decades among the computer graphics community. The need for plausible real time animations has generated a number of approaches, most of them focused on the simulation of cloth and facial expressions. Currently, in order to achieve interactive frame rates, explicit integration and mass-spring models must be used. FEM-based models and implicit integration results in the need for solving large linear systems, which makes them unfeasible for interactive applications.

However, using explicit methods leads to instability problems when solving stiff equations for large time steps: the time step must decreased rapidly with stiffer equations.  The interactive simulation of stiff deformable objects is thus an unsolved problem. Therefore, since interactive frame rates must be achieved in order to present useful feedback to the user, this problem is well suited for the application of the high programmability of current graphics hardware.

In the last years, GPUs have become high performance SIMD processing units. The new features of last graphics engines approaches them to more general purpose processing units which have been utilized recently to perform tasks not directly related to the original purpose they were built for (see GPGPU[2]). In this project, we exploit these new features provided to develop a GPU-based simulation system for deformable tetrahedral meshes. Our simulator includes implicit and explicit integration methods for solving the equation describing the dynamics of the physical system. To increase the range of applications to surgical training and pre-operative planning, we coupled our simulation system with a GPU-based raycaster for tetrahedral meshes, modified to support deformable meshes. This will provide the user with insights of the inner structures of the deformed model, which is a key issue in medical applications.

Technical details about the implementation can be found in an accompanying publication[3] to appear in the Simulation Theory and Practice Journal.

  Results    
Some examples of the results obtained are shown below. Promising frame ratios were achieved with both explicit and implicit methods. Further numerical methods are to be implemented and included in the simulator.

[4] [5]
[6] [7]
Bar model
Download Video[8]

[9] [10]
[11] [12]
Dolphin model
Download Video[13]

 

[14] [15]

Tetrahedral mesh of the Foot dataset

 

 

  Contact    
Eduardo Tejada[16]

  References    
[TE05] E. Tejada and T. Ertl.
Large Steps in GPU-based Deformable Bodies Simulation,
Simulation Theory and Practice. Special Issue on Special Issue on Programmable Graphics Hardware. To appear . 2005

(See also the list of publications of the institute[17].)

*This work is partially supported by the German Academic Exchange Service with Grant Nr. A/04/08711.

      University of Stuttgart, Institute for Computer Science,
Visualization and Interactive Systems Group

http://www.vis.uni-stuttgart.de/eng/research/fields/current/deformable/index.html