Modélisation et Animation de Matériaux Hautement Déformables en Synthèse d'Images

In this thesis, we are dealing with computer graphics modeling and animation of highlydeformable materials. Our work is aimed at creating virtual physically-based models of mat-ter, able to automatically deform due to interactions with the environment. Coping withlarge deformation is known to be time consuming, so efficiency and visual quality are thekey issues as they can open avenues such as surgery simulation or virtual reality in general.After a review of previous related work, we present a hybrid model for highly deformablematerials that combines implicit surfaces and a particle system. It results in a global modelthat gathers the advantages of the two approaches, and other valuable properties as volumepreservation. Then we discuss conventional particle system weaknesses. An alternative modelis thus proposed allowing a space-time adaptative simulation, where particles can subdivide tobetter discretize fast deforming areas, or merge to simplify stable regions. Computations aretherefore stable and optimized as discretization is automatically adapted. Lastly, an activeimplicit skin model is introduced. This deformable surface can coat any deformable modelboth providing a neat visualization and confering physical properties such as surface tension.More generally, it offers an efficient yet low-cost technique to visualize adaptive models,avoiding “popping” effects through smoothing of sudden internal change of granularity.The new models we developed seem to promise a fully adaptive simulation of deformableobjects as computations are minimized to ensure a given accuracy and focussed where needed.