Fast Multi-Body Coupling for Underwater Interactions

Tianhong Gao, Xuwen Chen, Xingqiao Li, Wei Li, Baoquan Chen, Zherong Pan, Kui Wu, Mengyu Chu

Pacific Graphics Conference Papers, Posters, and Demos, 2025. The Eurographics Association.

Abstract

Simulating multi-rigid-body interactions in underwater environments is crucial for various downstream applications, such as robotic navigation, manipulation, and locomotion. However, existing approaches either rely on computationally expensive volumetric fluid-rigid simulations or focus solely on single-body dynamics. In this work, we introduce a fast framework for simulating multi-rigid-body coupling in underwater environments by extending the added mass paradigm to capture global interactions in incompressible, irrotational fluids. Our method solves a Boundary Integral Equation (BIE) for the potential flow field, from which we derive the governing equation of motion for multiple underwater rigid bodies using a variational principle. We evaluate our method across a range of underwater tasks, including object gripping and swimming. Compared to state-of-the-art volumetric fluid solvers, our approach consistently reproduces similar behaviors while achieving up to 13× speedup. The example source code is available at https://github.com/guesss2022/fastMBCUI.

Official publication: Eurographics Digital Library. The open-access paper is © 2025 the authors and published under a Creative Commons Attribution license.