How to animate InstancedMesh objects?

Hi !
I’m confronted to a new issue…
So, i have a group composed by a sphere which is a simple Mesh, and three plane which are InstancedMesh.
All is very well displayed, but i want to rotate each of my InstancedMesh objects, but i don’t know why it doesn’t work…

Here is my function to update my objects (called at each frame) :

function animateParticles(time){
    var dummy = new THREE.Object3D()
    for (let i = 0; i < particleCount; i++) {
        dummy.position.x = Math.cos(time*Math.PI/180 * 100)
        dummy.position.y = Math.sin(time*Math.PI/180 * 100)
        dummy.position.z = sphereMesh.position.z
        spaceDustMesh.setMatrixAt(i, dummy.matrix)

time is the elapse time calculated at each frame. The function to update x and y is correct, i tried it directly on my sphere, and it work great.
Can you help me please ?

You also need the following line after your for loop:

spaceDustMesh.instanceMatrix.needsUpdate = true;

also, better hoist the o3d out

const dummy = new THREE.Object3D()
function animateParticles(time) {

otherwise this is what you’d re-create every frame.

Thank you ! It works

Oh yeah I did not notice this mistake, thanks