Avalanche is a natural disaster in the snow-covered mountainous area in winter, which may cause great disasters to human life and property. It is also a danger for skiers and climbers. This paper presents a new physically based algorithm to simulate the dynamic avalanches under position-based dynamics framework. To realistically simulate avalanches’ dynamic characteristics, we introduce the Bingham plastic model from geodynamics to model snow flow motion in avalanches. The interaction between snow flow in the avalanche and the surrounding objects is simulated by a level set-based two-way fluid–solid coupling model. We also propose static and kinetic friction mixed model to determine the accumulated transition of the avalanche. To create an avalanche scene with more realistic details, we employ an aerodynamics-based snow drag force model to generate snow fog effect. Finally, by choosing different criterion shear rate and friction parameters, different kinds of wet and dry avalanche scenes are realistically rendered. Compared with the real photographs of avalanches, our simulated results are quite satisfactory.

Landslide is a disaster which may cause huge losses of human life and block the traffic on hilly area. In this paper, we present a new physically based model to simulate the dynamic flow of landslides, under a modified MPM (material point method) framework. To realistically simulate the characteristics of fracture and flow of soil medium in landslide, we introduce the modified Cambridge clay model (MCCM) from soil dynamics into the yield surface criterion to model the dynamic process of landslides. The interaction between soil and rock in the landslide is simulated by a level-set-based two-way fluid–solid coupling algorithm. Meanwhile, we propose a GPU-based optimization to calculate the signed distance function in level set to improve the efficiency of collision detection. We also simplify the hardening and softening parameter calculation algorithm of MCCM to reduce the calculation involved in landslide simulation. By choosing different values of the material yield surface parameters, various kinds of landslide disaster scenes with different cover area are successfully generated, including rocks rolling from hill, soil and rock collapsing, landslide flowing, and covering the road and cars. Experimental results demonstrate the potential of our method.