Weekly Seminar
Repulsive Shells
Josua Sassen (École normale supérieure Paris-Saclay (France))
Thu, 08 May 2025 • 10:15 coffee/tea: EDDy's room 256, bldg 1953 // 10:45-11:45 talk in 008 • Pontdriesch 14, room 008 SeMath (host: Heiko von der Mosel)

Abstract

In this talk, we will discuss a shape space framework for collision-aware geometric modeling, where basic geometric operations automatically avoid interpenetration. Shape spaces are a powerful tool for surface modeling, shape analysis, nonrigid motion planning, and animation, but past formulations permit nonphysical intersections. Our framework augments an existing shape space using a repulsive energy such that collision avoidance becomes a first-class property, encoded in the Riemannian metric itself. In turn, tasks like intersection-free shape interpolation or motion extrapolation amount to simply computing geodesic paths via standard numerical algorithms. To make optimization practical, we develop an adaptive collision penalty that prevents mesh self-intersection. The final algorithms apply to any category of shape, and do not require a dataset of examples, training, rigging, nor any other prior information. For instance, to interpolate between two shapes we need only a single pair of meshes with the same connectivity. We evaluate our method on a variety of challenging examples from modeling and animation.