motionby

Motionby is a term used in certain animation and robotics contexts to describe a method of producing motion primarily through the arrangement and interaction of constraints, forces, and passive dynamics, rather than through explicit motion scripting or keyframing. In practice, motionby systems establish a network of joints, actuators, and contact interactions and rely on physics-based simulation to generate movement that appears natural.

The term has no single canonical origin and is used in niche discussions to contrast constraint-driven, physics-based generation of movement with traditional keyframed animation. It emphasizes motion that emerges from the physical configuration and environment rather than from manually authored trajectories.

Typically, motionby implementations employ inverse dynamics, constraint solvers, and optimization to satisfy energy, momentum, and contact constraints. Procedural rules, joint limits, friction models, and external forces guide the result. Hybrid pipelines may combine motionby with hand-authored keyframes to provide both realism and control.

Applications include game development, robotics simulations, and film visual effects, where realistic locomotion, balance, and object interaction can be produced with reduced keyframe effort and greater consistency across characters and scenarios. However, motionby can introduce unpredictability and require substantial computational resources and careful parameter tuning to achieve stable results.

Related topics include procedural animation, physics-based animation, inverse dynamics, constraint-based motion planning, and motion capture.