Simulation of Deforming Elastic Solids in Contact: Toward Automatic, Realistic Human Motion from 3D Scans

Much of my work has been devoted to a new, fast approach to computing material depth. By material depth, I mean the shortest path to the surface from any given point in a volume of an object.


I compute material depths using Level Set methods. Gentaro Hirota was kind enough to use my new method of computing material depths in a prior application. In this application however, the material depths were computed using a brute force projection search.
Regardless, this work shows a useful application for deformed distance fields. Please see http://www.cs.unc.edu/~sfisher/Research/DDF.html for further work on the deformation and the fast computation of distance fields.



An Application

This work uses material depth to compute penalty forces to resolve penetration in an FEM algorithm. The FEM algorithm is the work of Gentaro Hirota here at UNC. He should finish his dissertation in the coming months.

Data from the Visible Human Project was used to generate a model of a human leg. The data was segmented by hand into the various components of the leg.

This next sequence of images is rendered with pseudocolors so that you can visualize the material depth of each component of the leg model.

These next two images show the realistic folding of skin and bulging of muscle that naturally results from the FEM method. Observe the skin in the crease of the knee.


The natural looking bulging of muscle is due to the simulation of the underlying structure of the leg. These renderings use transparency to reveal the intricate details of the internal structure of the leg.



An Animation Using the Simulation Results

The models of the leg generated by the deformation program were pulled in to A|W Maya for use in a short Frankenstein spoof. I use MEL scripting to automate the process of linking together our similator and Maya (for additional animation and rendering).

One screenshot is given. Please see the movie files for the complete animation.







Movie Files

I apologize for the large size of the files, but if you are that interested, they are worth the wait. Zipping/compressing the files is essentially useless as you can only get about 5-8% packing on most quicktime files.

Cross Section of Knee Bending I - compressed quicktime - 8.2 MB
Cross Section of Knee Bending II - compressed quicktime - 7.0 MB
BEST - Opaque to Transparent Knee Bending - compressed quicktime - 5.9 MB
Transparent Knee Bending - quicktime - 5.9 MB
Animated Application (large file) - quicktime - 11.5 MB