Deformable

Deformable is an adjective describing objects or materials that can change shape under applied forces. In contrast to rigid bodies, which resist change in shape and size, deformable bodies experience displacement, strain, or rotation when subjected to stresses. Deformation can be temporary or permanent, and is governed by the material's constitutive relations.

In physics and engineering, deformation is analyzed with continuum mechanics. Elastic deformation is reversible: once the load is removed, the object returns to its original shape. Plastic deformation is permanent, occurring after yielding. Most real materials exhibit a combination of elastic and plastic behavior, often described by constitutive models and stress-strain curves. Time-dependent effects like viscoelasticity, creep, and fatigue add further complexity.

In computational modeling, deformable objects are simulated to predict behavior under loads. Finite element analysis (FEM) and other numerical methods model the material's response by discretizing the body into elements. Simpler real-time simulations may use mass-spring systems, position-based dynamics, or mesh-free methods. In computer graphics and animation, deformable models enable realistic motion of skin, muscles, and soft tissues through rigging, skinning, and physics-based deformations. Techniques range from hierarchical skeletons with controls to data-driven or physically based simulators.

Applications span engineering design, structural analysis, medical device testing, soft robotics, and computer graphics. Deformable objects present challenges such as nonlinear material behavior, large deformations, contact, and instability, requiring appropriate models and numerical methods to ensure accurate and stable results.