Welcome to the Computer Animation Group at RWTH Aachen University!

The research of the Computer Animation Group focuses on physically-based simulation of rigid body systems, deformable solids, and fluids, collision handling, cutting, fracturing, and real-time simulation methods. The main application areas include virtual prototyping, simulation in engineering, medical simulation, computer games and special effects in movies.


Best Paper Award

Our paper "Consistent SPH Rigid-Fluid Coupling" got the best paper award at the Eurographics Vision, Modeling, and Visualization 2023.

Sept. 29, 2023

Implicit Density Projection now available on GitHub!

The code for our paper "Implicit Density Projection for Volume Conserving Liquids" has been implemented in the open source project Mantaflow and is now available on GitHub. Check here for the most recent version.

July 27, 2022

Best Paper Award

Our paper "Fast Corotated Elastic SPH Solids with Implicit Zero-Energy Mode Control" got the best paper award at the ACM SIGGRAPH / EUROGRAPHICS Symposium on Computer Animation 2021.

Sept. 10, 2021

Best Paper Award

Our paper "Volume Maps: An Implicit Boundary Representation for SPH" got the best paper award at the ACM SIGGRAPH Motion, Interaction and Games.

Nov. 15, 2019

Best Paper Award

Our paper "A Micropolar Material Model for Turbulent SPH Fluids" got the best paper award at the ACM SIGGRAPH / EUROGRAPHICS Symposium on Computer Animation.

Aug. 15, 2017

SPlisHSPlasH now available on Github!

SPlisHSPlasH is an open-source library for the physically-based simulation of fluids. The simulation in this library is based on the Smoothed Particle Hydrodynamics (SPH) method which is a popular meshless Lagrangian approach to simulate complex fluid effects. Check it out here!

Nov. 17, 2016

Recent Publications

STARK: A Unified Framework for Strongly Coupled Simulation of Rigid and Deformable Bodies with Frictional Contact

2024 IEEE International Conference on Robotics and Automation (ICRA)

The use of simulation in robotics is increasingly widespread for the purpose of testing, synthetic data generation and skill learning. A relevant aspect of simulation for a variety of robot applications is physics-based simulation of robot-object interactions. This involves the challenge of accurately modeling and implementing different mechanical systems such as rigid and deformable bodies as well as their interactions via constraints, contact or friction. Most state-of-the-art physics engines commonly used in robotics either cannot couple deformable and rigid bodies in the same framework, lack important systems such as cloth or shells, have stability issues in complex friction-dominated setups or cannot robustly prevent penetrations. In this paper, we propose a framework for strongly coupled simulation of rigid and deformable bodies with focus on usability, stability, robustness and easy access to state-of-the-art deformation and frictional contact models. Our system uses the Finite Element Method (FEM) to model deformable solids, the Incremental Potential Contact (IPC) approach for frictional contact and a robust second order optimizer to ensure stable and penetration-free solutions to tight tolerances. It is a general purpose framework, not tied to a particular use case such as grasping or learning, it is written in C++ and comes with a Python interface. We demonstrate our system’s ability to reproduce complex real-world experiments where a mobile vacuum robot interacts with a towel on different floor types and towel geometries. Our system is able to reproduce 100% of the qualitative outcomes observed in the laboratory environment. The simulation pipeline, named Stark (the German word for strong, as in strong coupling) is made open-source.

Simulation of wire metal transfer in the cold metal transfer (CMT) variant of gas metal arc welding using the smoothed particle hydrodynamics (SPH) approach

Materials Science and Engineering Technology

Cold metal transfer (CMT) is a variant of gas metal arc welding (GMAW) in which the molten metal of the wire is transferred to the weld pool mainly in the short-circuit phase. A special feature here is that the wire is retracted during this strongly controlled welding process. This allows precise and spatter-free formation of the weld seams with lower energy input. To simulate this process, a model based on the particle-based smoothed particle hydrodynamics (SPH) method is developed. This method provides a native solution for the mass and heat transfer. A simplified surrogate model was implemented as an arc heat source for welding simulation. This welding simulation model based on smoothed particle hydrodynamics method was augmented with surface effects, the Joule heating of the wire, and the effect of the electromagnetic forces. The model of metal transfer in the cold metal transfer process shows good qualitative agreement with real experiments.

Ray tracing method with implicit surface detection for smoothed particle hydrodynamics-based laser beam welding simulations

Materials Science and Engineering Technology

An important prerequisite for process simulations of laser beam welding is the accurate depiction of the surface energy distribution. This requires capturing the optical effects of the laser beam occurring at the free surface. In this work, a novel optics ray tracing scheme is proposed which can handle the reflection and absorption dynamics associated with laser beam welding. Showcasing the applicability of the approach, it is coupled with a novel surface detection algorithm based on smoothed particle hydrodynamics (SPH), which offers significant performance benefits over reconstruction-based methods. The results are compared to state-of-the-art experimental results in laser beam welding, for which an excellent correspondence in the case of the energy distributions inside capillaries is shown.

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