Modelling, Simulating and Visualizing Granular Materials

The shape and the motion of dunes are most imprcssive and beautiful scenes. Granular materials in general and sand in particular display a variety of behaviours, that are in many ways different from those of either liquids or solids. These behaviours are very partially understood. The objective of this work is, on the one hand, the understanding of the macroscopic behaviour of this type of material, and on the other hand, the achievement of animation sequences for artistic purposes. The grain models described here were implemented and simulated according to ttrc Cordis-Anima formalism. This means that physical objects in general, and granular material in particular, are considered as a set of punctual masses linked together by linear or non-linear spring-damper interactions. These granular objects were visualized thanks to the engraved screez algorithm: this "screen " is a physically simulated carving plate acting as a visualization support. The models and simulations produced here account for comple>: phenomena such as the constitution of a pile from independant padcles, as well as avalanch and internal collapse phenomena. I