Déformation et découpe interactive de solides à géométrie complexe

français

25/10/2012 - 14:00 Mr Guillaume Bousquet (Université de Grenoble) Grand Amphi de l'INRIA Rhône-Alpes, Montbonnot

Keywords :
  • repères déformables
  • skinning
  • méthodes particulaires
  • éléments finis
  • simulation chirurgicale
Physically based deformable models have become ubiquitous in computer graphics. It allow to synthetize real behaviors, based on the physical laws from continuum mechanics. In this thesis, we focus on interactive simulations such as to video games or surgical simulators.

The majority of the existing works focused up to here on the animation of objects made of homogeneous materials. Nevertheless, plenty of real objects, for instance like the biological structures, consist of multiple imbricated materials. Their decomposition in homogeneous zones requires a high-resolution spatial discretization to solve the variations of the material properties, which requires prohibitive computation time.

In this context, we present new real time simulation techniques for deformable objects which can be cut.

First of all, we present a real time method for cutting deformable objects in which, contrary to the previous methods, the object deforms on the cutting tool contact and cuts occur only when the pressure reaches a certain level. The independence of the physical, collision and visual models makes the topological changes easier. The GPU computing and local modifications enable fast execution.

Then, a dynamic meshless method is described, which uses reference frames as control nodes instead of using points, with a displacement field formulation similar to skinning. It allows to easily tune the weights and benefits from the rigor of physical methods as the finite elements. The introduction of integration points, reducing the samples number by a least squares approximation, speeds up the spatial integrations. Other pre-computations are proposed in order to speed up the simulation time.

Finally, new anisotropic shape functions are defined to encode the variations of material properties thanks to the introduction of the compliance distance. These complex shape functions uncouple the material resolution of the displacement functions ones. It allow an extremely sparse nodes sampling. The use of the compliance distance allows an automatic nodes distribution with regard to the material properties.

President:

Mr Denis Favier (Professeur - Université Joseph Fourier)

Directors:

  • Mr François Faure (Professeur - Université Joseph Fourier )

Raporteurs:

  • Mr Hervé Delingette (Directeur de Recherche - INRIA )
  • Mr Yannick Remion (Professeur - IUT de Reims )

Examinators:

  • Mr Jérémie Allard (Chercheur - INRIA )
  • Mr Yohan Payan (Chercheur - CNRS )
  • Mr Denis Favier (Professeur - Université Joseph Fourier )