Particle-based animation of complex materials in computer graphics

• Applicant: Professor Dr. Jan Stephen Bender
• Subject Area: Image and Language Processing, Computer Graphics and Visualisation, Human Computer Interaction, Ubiquitous and Wearable Computing
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543332027

Physically-based animation plays an important role in many computer graphics applications such as visual effects in movies, computer games or virtual reality. In this research area particle-based animation methods have become popular in recent years since they support topology changes, facilitate phase transitions and enable a unified representation of solids and fluids which simplifies the coupling of different physical models. An important and in computer graphics well-established particle-based simulation approach is Smoothed Particle Hydrodynamics (SPH) which enables complex multi-physics simulations. In this project we aim to develop novel SPH methods to extend the SPH framework by complex material models and physical phenomena. In the first step of the project we want to develop a new SPH simulation method for granular materials. In the simulation we plan to model friction by using an elastoplastic material model. This model should be combined with the Drucker-Prager yield criterion so that only small friction forces act on particles with low pressure. Since the criterion depends on the pressure values, we want to investigate a strong coupling of the new method with the pressure solver. Each SPH computation requires the particle information in a three-dimensional neighborhood. Therefore, it is not directly possible to simulate materials with an almost one- or two-dimensional structure such as hair, ropes or textiles. Since such materials play an important role in computer graphics applications, the goal of our second work package is to develop a codimensional simulation method which solves this problem. The idea of the method is to locally approximate the simulated geometry at each point by a curved surface or a curve. The SPH computations are then performed in the lower dimension of the approximation. Moreover, we plan to develop a particle-based model for the simulation of bending and torsion forces. An important aspect when extending the SPH framework by new materials is that they can be easily coupled with others due to the unified SPH formulation. However, a simple coupling of sand or textiles with water does not yield a realistic material behavior since the materials are porous. This means that they can absorb and diffuse fluid which leads to a change of the material behavior. In the last part of the project we want to simulate this effect. We plan to develop a novel SPH method for the simulation of porous materials which considers pressure forces, capillary forces as well as cohesion and adhesion forces. Overall, this project aims to significantly expand the SPH framework and further establish it in computer graphics.

• DFG Programme: Research Grants