Fluids and Granular Materials
Fluid produce some of the most rich and vivid phenomena in computer animation. Due to their constantly changing topology, they pose higher computational challenges than solid objects. Granular materials show a dramatically variable dynamic behavior, sometimes like a fracturing solid, other times like a flowing liquid, or even like a exploding gas. In our work we seek methods that provide a better balance between realism and computational cost for the simulation of fluids and granular materials.
Granular Flow Using Particle Methods
Combining mechanical properties of solids and fluids, granular materials pose important challenges for the design of algorithms for realistic animation. In (Alduán et al. 2011), we present a simulation algorithm based on smoothed particle hydrodynamics (SPH) that succeeds in modeling important features of the behavior of granular materials. These features are unilateral incompressibility, friction and cohesion. We extend an existing unilateral incompressibility formulation to be added at almost no effort to an existing SPH-based algorithm for fluids. The main advantages of this extension are the ease of implementation, the lack of grid artifacts, and the simple two-way coupling with other objects. Our friction and cohesion models can also be incorporated in a seamless manner in the overall SPH simulation algorithm.
Multi-Resolution Granular Simulation
Granular materials enjoy vivid motion phenomena that make them highly visually attractive. However, simulating each and every physical grain imposes an extremely high computational cost, due to the stringent resolution requirements. In (Alduán et al. 2009), we introduce a method for simulating granular media that achieves high visual resolution and high mechanical fidelity at a lower computational cost than earlier methods. Our method is based on a novel spatial decomposition of the computation of internal and external forces. The method is also highly parallelizable and configurable, allowing the artist to simulate a large range of granular materials.