Add Rapier rigid bodies, colliders, forces, sensors, and joints to React Three Fiber. Use for collision-driven movement and simulation; use animation guidance for purely visual motion.

React Three Fiber physics Check installed Fiber, React, and Rapier versions. Rapier 2 targets Fiber 9 / React 19; older projects need their compatible package line. Keep rendering and simulation ownership separate. Falling and clickable body Mount beneath Canvas with lighting. Physics loads WASM asynchronously; include Suspense. Cuboid collider arguments are half extents, unlike BoxGeometry's full dimensions. Bodies and colliders Dynamic bodies respond to forces. Fixed bodies represent static surfaces. Position kinematic bodies use setNextKinematicTranslation/Rotation ; velocity kinematic bodies use linear/angular velocity setters. Set initial transforms on RigidBody. Do not animate a simulated mesh's position in useFrame ; the physics world remains authoritative and interpolation can overwrite it. Prefer simple colliders or compound convex shapes. Use trimesh mainly for static concave environments; a hull closes holes and cannot preserve arbitrary concavity. Set colliders={false} when supplying complete manual colliders, otherwise automatic colliders may be added as well. Collider sizes/transforms must match world scale; use debug rendering to inspect them. Choose collider density/mass consistently and avoid accidental duplicate mass from overlapping auto/manual colliders. For many repeated bodies, InstancedRigidBodies reduces rendering overhead, not the cost of simulating each body. Keep instance keys/transforms stable. Forces and simulation time An impulse is a one time momentum change. A force persists until reset; repeated addForce calls accumulate. Do not add the same continuous force every render frame without an explicit force management strategy. Use useBeforePhysicsStep for input/forces that must align with simulation ticks. If a controller owns all user forces on a body, it can reset and reapply them per tick; coordinate with other force sources before resetting. Kinematic targets should advance on physics steps. Teleporting with setTranslation is different from kinematic movement and can bypass expected collision response. Prefer a fixed timestep for stable behavior. timeStep="vary" trades predictability for variable stepping; multiplying values by render delta does not make the physics deterministic. For demand rendering, use Physics updateLoop="independent" so active bodies can request renders. A sleeping world should not force unnecessary rendering. Let bodies sleep; explicitly wake them when applying actions that need it. Enable CCD for fast/small bodies when tunneling warrants its cost. Events, sensors, and joints Sensors report intersection enter/exit without contact response. Use sensor intersection events rather than expecting ordinary collision events. Collision groups require compatible membership/filter masks on both colliders. Use interactionGroups instead of hand building masks unless the format is needed. Collision payloads may lack a rigidBodyObject for standalone colliders. Inspect the other collider/body safely; do not assume every hit is a named mesh. Follow the installed Rapier callback restrictions. In contact filter hooks, cache body state before the step rather than querying it during Rust's borrowed simulation state. Joints connect body refs using local anchors and axes, not world coordinates. Check the hook's exact tuple shape for fixed, revolute, spherical, spring, or rope constraints. Read [controlled motion and joints](references/controllers.md) for a step aligned kinematic platform and correctly aligned hinge. A collision aware character controller is separate from moving a mesh or setting a dynamic body's position. Use the installed Rapier character controller API and test stairs/slopes/grounding. Restoring a world snapshot requires matching body creation/handle relationships; it is not a generic way to swap arbitrary scenes beneath existing React refs. Verify Check resting contact, collider alignment, impulses, sleeping/waking, and different render frame rates. Test sensor enter/exit, fast body tunneling, and Strict Mode remounts for the paths used. Sources [React Three Rapier](https://github.com/pmndrs/react three rapier), [API reference](https://pmndrs.github.io/react three rapier/). [Rapier rigid bodies](https://rapier.rs/docs/user guides/javascript/rigid bodies), [colliders](https://rapier.rs/docs/user guides/javascript/colliders), [character controller](https://rapier.rs/docs/user guides/javascript/character controller).

r3f-physics