enzed/r3f-skills

r3f-animation

Animate React Three Fiber objects with useFrame, damping, and GLTF clips.

View source
Original skill document

Rendered from the source repository. Headings, examples, code, tables, links, and referenced images are preserved.

React Three Fiber animation

Check installed Fiber, Drei, and React versions first. These examples target Fiber 9 / React 19. Keep the project's animation library when it already meets the task.

Choose an owner

  • Use useFrame and refs for continuous transforms/uniforms; React state describes discrete goals such as selected, open, or active.
  • Use Drei useAnimations for authored GLTF clips. Read clip playback for independent animated instances and cleanup.
  • Use the project's spring/tween library for coordinated transitions; check its React peer dependencies before adding it. Do not introduce a state manager merely to animate a mesh.
  • Let Rapier own simulated body transforms. Animate kinematic targets through physics APIs rather than fighting the simulation with mesh positions.

Damping that can return to idle

Mount below Canvas; this also works with frameloop="demand". Click the box to change its target.

tsx
import { useEffect, useRef, useState } from 'react'
import { useFrame, useThree } from '@react-three/fiber'
import { MathUtils, type Mesh } from 'three'

export default function Example() {
  const mesh = useRef<Mesh>(null)
  const [active, setActive] = useState(false)
  const invalidate = useThree((state) => state.invalidate)
  const target = active ? 1 : -1
  useEffect(() => { invalidate() }, [target, invalidate])

  useFrame((_, delta) => {
    if (!mesh.current) return
    // Cap a visual transition's resume jump, not a physics simulation step.
    const x = MathUtils.damp(mesh.current.position.x, target, 6, Math.min(delta, 0.1))
    const moving = Math.abs(x - target) > 0.001
    mesh.current.position.x = moving ? x : target
    if (moving) invalidate()
  })

  return (
    <mesh ref={mesh} name="moving-box" onClick={() => setActive((value) => !value)}>
      <boxGeometry />
      <meshStandardMaterial color={active ? 'orange' : 'coral'} />
    </mesh>
  )
}

Timing and performance

  • delta is seconds. Integrate velocity as position += velocity * delta; use MathUtils.damp or lerp with 1 - exp(-lambda * delta) for exponential smoothing. A fixed lerp fraction depends on refresh rate; delta * speed can overshoot.
  • Reuse vectors/quaternions; avoid allocating them in every frame. Use quaternion interpolation for orientation instead of independently lerping Euler angles across wrap boundaries.
  • Use one timeline/clock owner. Fiber 9 still supplies state.clock; do not replace Fiber internals because Three.js deprecated new standalone Clock instances. For independent Three.js timing, consult Timer in the installed release.
  • On demand, external animation systems need invalidation while active. Invalidate before starting a synchronous animation and arrange the start on the next frame if the first frame would otherwise jump.
  • Read fast external state directly in the frame callback when supported (e.g. a store's getState()); subscribe React only to UI-relevant changes. Clean up external subscriptions.
  • Do not claim a normal React re-render stops animation. Profile actual work and subscription frequency before memoizing components.
  • Hiding an object does not stop its frame callback or mixer. Pause expensive animation explicitly when appropriate; respect reduced-motion preferences for decorative motion.
  • Repeated oscillations and shader motion can derive phase from elapsed time; simulations needing reproducibility require a fixed-step design, not arbitrary delta clamping.

Verify

Compare motion at different frame rates, background/resume behavior, and repeated target changes. On demand, confirm the object wakes, reaches its goal, and stops requesting frames. For clips, test two instances playing different actions.

Sources

from this repository

More skills

All skills