bounding box for skinned mesh

[mshamaseen]

Describe the bug

I am not sure if this a gltf bug or a three js bug but when exporting a skinned mesh with an armature with a specific scale the bounding box will not work correctly, for example, I have an object with an armature of scale 0.018 for all axes and a mesh child with a scale of 1; what happens when I import it to threejs/editor is the bounding box take the scale of the armature, as the image below:

and, via coding, when I try to get the object size by:

let measurementBox = new THREE.Box3().setFromObject( this.threeJsObject ); measurementBox.getSize(this.objectSize);

the result is the armature mesh child size (after scaling) multiplied by the armature scale again!
This means if the x dimension of a mesh after being scaled by an armature is 100 with a scale of 0.5 in the armature (actual size of the mesh is 200 then), the bounding box x size will be 50 and not 100, it will scale too after the mesh!

To Reproduce
here is the file that I am using, the armature scale is 0.018 and the bounding box is 0.018 of the actual size of the mesh rather than being 100% of the actual size of the mesh.

https://drive.google.com/file/d/14Iq0pUmHt1uE3F0brMIVfFL5taV2MEZs/view?usp=sharing

Steps to reproduce the behavior:

1. just import it in threejs/editor and check the bounding box!

Expected behavior

the bounding box surrounds all the mesh and not being multiplied with the armature scale, it should be like the image below:

Platform:

• Device: Desktop
• OS: Linux, ubuntu
• Browser: All
• Three.js version: r120

[gkjohnson]

This is a known issus with SkinnedMesh bounding boxes -- there are some related discussions in #18334, #18245, #14499

[Mugen87]

Marking this as a duplicate of #14499.