Description:
Three.js does not have built-in physics, but can integrate seamlessly with libraries like:
- Cannon.js / cannon-es (lightweight, good for rigid bodies and VR).
- Ammo.js (Bullet-based, accurate but heavier).
- Rapier.js (WASM-based, high performance for complex interactions).
Physics simulation includes rigid bodies, constraints, raycasting, vehicle physics, collision detection, and more.
When integrating physics:
- Use THREE.BufferGeometryUtils.mergeVertices() for mesh optimization.
- Sync physics body and Three.js mesh via mesh.position.copy(body.position) on each frame.
- Use ConvexPolyhedron or Trimesh for accurate mesh shapes.
Use Cases:
- VR education platforms with robot assembly and simulations.
- Interactive scenes with hoverboards, elevators, or vehicles.
- Multiplayer physics-based games.
Advantages:
- Enables real-world interactions and simulations.
- Rapier.js and Ammo.js are optimized for large physics scenes.
- Syncs well with animations, XR controls, and player controllers.
Limitations:
- Physics sync adds CPU load in real-time.
- Requires careful timestep and update strategy (fixed vs delta-based).
- Trimesh shapes are expensive; should be used sparingly.