DynaBeam: From Motion-Driven Parameter Identification to Real-Time Physical Simulation of 3D Vegetation

Our 3D world is filled with vegetation that is often in motion due to interactions with wind and other physical forces. While recent representations excel at capturing and generating these dynamic scenes, extracting their underlying physics traditionally requires computationally heavy inverse simulations or appearance-based learning that struggle with speed and generalization. In this work, we introduce DynaBeam, a framework that models dynamic 3D vegetation, ranging from houseplants to trees, as hierarchical graphs of connected beam elements. We show that the geometric structure and motion of these beams provide a strong enough signal to efficiently extract both the intrinsic physical parameters like stiffness and the external forces driving the movement. By explicitly separating geometry, motion, and force, DynaBeam bypasses expensive simulation solvers to achieve accurate dynamic scene reconstruction in mere seconds. Furthermore, because we recover physical parameters rather than fitting visual patterns, our representation natively supports real-time physical simulation under entirely new and unobserved forces. Extensive evaluations show that DynaBeam delivers faster and more accurate physical inversion and forward simulation than prior methods, enabling interactive animation and physical reconstruction from real-world videos.