ESPEFs: Exponential Spring Potential Energy Functions for Simulating Deformable Objects

Extended Position-based Dynamics (XPBD) is a well-known method to carry out the simulation of deformable objects. It extends the Position-based Dynamics (PBD) algorithm with a compliance parameter for the material stiffness and implicitly adapts the damping function within the Gauss-Seidel iteration. Although the XPBD method improves upon PBD, it can be cumbersome to fine-tune the required parameters for the desired material properties of the deformable objects. In this paper, we introduce the exponential spring potential energy functions (ESPEFs) for the XPBD simulation of the deformable objects with reduced parameter adjustments. Our method reformulates the well-known spring potential energy functions on an exponential basis which provides more vivid motion during physics-based simulations. ESPEFs enrich the hyperelasticity of the deformable models without any additional effort while the classical methods require cumbersome parameter tunings with trial-and-error tests. To demonstrate the benefits of ESPEFs, we extensively compare our simulation results with the well-known spring models, strain-based dynamics including the constitutive materials and the output of another common iterative solver (Projective Dynamics). The resulting approach is simple, stable, interactive and produces visually pleasing results.