Regression in bounding box calculation for skinned meshes

[mattrossman]

Three.js r151 introduced bounding volumes for SkinnedMesh, see mrdoob/three.js#25612. This causes unexpected behavior with Box3.setFromObject()

Take for example this model: bobby.glb.zip

r150	r151

GLTFLoader doesn't update bone world matrices after a model loads (see mrdoob/three.js#24772) which means the SkinnedMesh.computeBoundingBox() call within Box3.expandByObject() can result in an incorrect bounding box.

A workaround is to call .updateMatrixWorld() on the object before calculating the bounding box.

three-gltf-viewer/src/viewer.js

Lines 251 to 257 in 83114d4

	setContent ( object, clips ) {
	this.clear();
	const box = new Box3().setFromObject(object);
	const size = box.getSize(new Vector3()).length();
	const center = box.getCenter(new Vector3());

+object.updateMatrixWorld()

 const box = new Box3().setFromObject(object);
 const size = box.getSize(new Vector3()).length();
 const center = box.getCenter(new Vector3());