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One mesh. Many bodies.

The official Jolt example turns two InstancedMesh objects into hundreds of physics bodies. This study keeps the indexed transform path visible: Jolt owns the bodies, Three.js owns the instance buffers.

Initializing Preparing renderer

Preparing WebGLRenderer, instanced buffers, and JoltPhysics...

physics: -
boxes: -
spheres: -
bodies: -
resets: -
draws: -
fps: -

Indexed body controlssetMeshPosition

Drop interval 0.75s

auto-reset random instances wireframe instance meshes

Click a box or sphere to select its instance index. Jolt exposes indexed repositioning, not a general impulse method in this wrapper.

Jolt contractinstanced bodies

await JoltPhysics()load the WASM-backed addon

mesh.userData.physicsdeclare mass/restitution

physics.addScene(scene)register floor + instances

setMeshPosition(mesh, p, i)recreate indexed body

instanceMatrix.needsUpdateupload Jolt transforms

The addon supports BoxGeometry, SphereGeometry, and IcosahedronGeometry, including InstancedMesh. Its current wrapper has no official collider helper, impulse, or remove-mesh method; those differences are part of the study.

Selected instancenone

source mesh-

instance index-

body type-

reposition API-

Jolt is loading. The external addon requires an active Internet connection and a page lifecycle that can tolerate its internal timer.

Based on the official Jolt instancing example. Orbit the field, select an instance, and use indexed repositioning to see how two shared InstancedMesh buffers can carry many physics bodies.

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