softbody

Softbody refers to deformable objects whose shapes change under applied forces, unlike rigid bodies that preserve shape except for rotation. In physics, computer graphics, and materials science, softbody dynamics study how properties such as elasticity, damping, and internal pressure govern deformation, contact, and fracture. The term covers a range of materials, from jelly-like spheres to inflatable membranes.

Modeling approaches include mass-spring systems, finite element methods, and position-based dynamics. Mass-spring models pair mass points connected by springs; they are simple and fast but can lack accuracy and stability for large deformations. FEM treats the object as a continuum and computes stress and strain using material constitutive models, offering higher realism at greater computational cost. Position-based dynamics solves constraints directly for stable, real-time behavior, often with reduced physical fidelity but good control over deformation.

Material behavior varies, including linear and nonlinear elasticity, viscoelasticity, and plasticity. Materials may be isotropic or anisotropic, and some soft bodies include internal pressure to simulate inflated shells or membranes.

In graphics, hollow soft bodies often use internal pressure to preserve volume. Applications span film and video game visual effects, surgical simulators, virtual prototyping, and soft robotics. In soft robotics, compliant actuators and pneumatic networks produce complex, safe deformations suited to delicate manipulation.

Challenges include balancing realism and performance, handling collisions and contacts, parameter estimation, and numerical stability. Researchers combine data-driven models with traditional physics to improve realism and control in interactive environments.