ThreeJS: Raycaster selecting old, wrong nodes

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1

so i’ve made made an update on my GLB files

image
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As you can see this is my chair in blender
And these are the child nodes that make up the figure of the chair:
image
As you can see its only an one child node
But this happens, when i setup raycaster to select one object of my scene and paint it random colour

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it doesnt paints the entire chair, it paints a part of the chair like if were more nodes to paint, i dont know
fun fact: in the past that was possible because the chair in blender was divided into various nodes, but i unified them, and overwrited the old .glb file. but it still happening like if it was reading an old .glb file. I restarted my project, and it doesnt worked

this is my raycaster code:

const raycaster = new three.Raycaster()

document.addEventListener('mousedown', onMouseDown)

function onMouseDown(event){
  const coords = new three.Vector2(
    (event.clientX / renderer.domElement.clientWidth) * 2 -1,
    -((event.clientY / renderer.domElement.clientHeight) * 2 -1)
  )

  raycaster.setFromCamera(coords, camera)

  const intersects = raycaster.intersectObjects(scene.children, true)
  if(intersects.length > 0){
    const selectedObject = intersects[0].object
    
    const color = new three.Color(Math.random(), Math.random(), Math.random())
    selectedObject.material.color = color
   
    console.log(`${selectedObject.name}`)
  }
}
2

It appears that—even though you unified your chair model in Blender—the exported GLB file may still contain multiple mesh parts (sub-objects) or retain a hierarchy from the previous version. When you use the raycaster, it returns the first intersected child node. This is why only part of your chair gets painted with the random color.

Here are a few steps to resolve the issue:

  1. Ensure You’re Loading the Updated GLB
    Sometimes the browser caches the old file. Try clearing your cache or appending a version query (e.g. model.glb?v=2) to force the browser to load the new file.
  2. Inspect the Model’s Structure
    Use a 3D viewer or log the scene’s hierarchy (for example, using console.log(scene.children)) to confirm whether the GLB now has only one mesh or still contains multiple child nodes. Even if the geometry appears unified in Blender, the export might have left several sub-meshes.
  3. Apply the Material Change to All Parts
    If the model still contains multiple mesh nodes, you can traverse the parent’s children so that every mesh receives the color change. For example, replace your material-change code with:
const selectedObject = intersects[0].object;
const color = new THREE.Color(Math.random(), Math.random(), Math.random());
// Traverse the parent hierarchy to update all meshes in the model:
selectedObject.parent.traverse(child => {
  if (child.isMesh) {
    child.material.color = color;
  }
});
console.log(selectedObject.name);
  1. Re-export with Proper Settings in Blender
    If you intended to have a single unified mesh, double-check your export settings in Blender. Use the “Join” operation and ensure “Apply Modifiers” is enabled so that the export truly merges all geometry into one mesh.

By following these steps, you should be able to have the raycaster paint your entire chair rather than only one part.

3

ohhh thank you very much, i didint know the existence of traverse() function, thanks!!

5

GLTF doesn’t support multiple materials on a single mesh… so when you export… you will get a mesh per material.

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