`MeshStandardMaterial().skinning = true` doesn't work with `scene.overrideMaterial`.

[will-ca]

Description of the problem

Assigning .skinning = true doesn't work when the material is assigned to scene.overrideMaterial:

scene.overrideMaterial = new THREE.MeshPhysicalMaterial({skinning: true})

The material and rendered image behave identically to as if .skinning === false.

Three.js version

• [ x ] r118

Browser

• All of them
• Chrome
• Firefox
• Webkit

[WestLangley]

Likely a duplicate of See #14577. See links for additional related posts.

[will-ca]

@WestLangley I saw and read that issue, and from my understanding, it's completely different (despite the deceptively similar titles and summaries).

#14577 is about selectively preserving effects from the originally assigned, un-overridden materials on each object while doing the final shading using the new override material. I.E. It's about combining arbitrary materials by processing the override material as if the shaded surfaces had modifications to their normal, depth, and other properties that would originally have been accounted for by the original, unoverriden material.

This issue is about properly handling a property of the new, override material. Resolving this issue does not require cleverly combining behaviours from multiple arbitrary materials; it only requires properly handling the already-implemented properties of one single material. Likewise, issue #14577 is at most an enhancement in severity because it describes a desired behaviour that extends beyond the documented and expected behaviour of overriding materials; whereas I believe this is more of an "issue" because it describes a situation where the presently documented behaviour of overriding materials fails, by failing to properly handle an already-existing feature of the override material.

This would be a duplicate of #14577 if it were asking for a way to deliberately ignore the .skinning property of the override material and instead use the .skinning property of the original material, but it's not. It's just reporting a case where the .skinning property of the override material on its own doesn't work.

[WestLangley]

scene.overrideMaterial = new THREE.MeshPhysicalMaterial( { skinning: true } )

Is everything in your scene a skinned mesh?

I think more info about your use case would be helpful. A simple live example may help to clarify your use case.

[will-ca]

@WestLangley

Is everything in your scene a skinned mesh?

In the scene I've tested, I believe every mesh object is a skinned mesh, yes.

That is not true of the Object3Ds, Groups, or scene background, however, the last of which also seems to be affected by scene.overrideMaterial.

I think more info about your use case would be helpful. A simple live example may help to clarify your use case.

I'm not sure my specific use case actually matters for this issue, so much as does the deviation from documented, expected, and self-consistent behaviour.

I'm also not sure what more relevant information there is:

There is a property that is documented as "forc[ing] everything in the scene to be rendered with that material", and another property that is documented as "Defin[ing] whether the material uses skinning".

When these two properties are used together, one of them breaks, to the effect that the material is always rendered as if skinning were disabled.

That is all there is to it.

A "simple live example" is also a bit tricky to me, because any live example of this must necessarily go through all the boilerplate of loading and animating a skinned mesh.

The reproducer I included in the original post is already only a single line long, and can be pasted into any scene with skinned meshes to show the issue.

However, here's an example based on the official example for skinned meshes:

https://jsfiddle.net/q8vm4tbd/

The first checkbox in the first section of the dat.gui window toggles the conditions of the issue. I hope I don't have to explain that having everything freeze in the T-pose when the override material is enabled is not what is expected to happen, nor is it what happens when the material is manually assigned to the skinned meshes.

As you can see, my "use case" is irrelevant here. This issue is about a feature that is described in the documentation, and which works great in most other situations, but is broken in this condition.

[WestLangley]

I think it is still true that Materials cannot be shared between skinned and non-skinned meshes. That would apply to overrideMaterial, too. In your fiddle, removing the ground plane solves the problem.

https://jsfiddle.net/pv3aLoc5/

Is everything in your scene a skinned mesh?

In the scene I've tested, I believe every mesh object is a skinned mesh, yes.

Can you please check again?

[will-ca]

Huh. It looks like there are a bunch of Object3D's, especially at the ends of each bone chain:

JSON.stringify((function hierarchy(obj) {return [obj.constructor.name, obj.children.map(hierarchy)];} )(scene), null, 0)

["Scene",[["Group",[["Object3D",[["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]],["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Object3D",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Object3D",[["Object3D",[]]]]]]]]]]]]]]]],["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]],["Bone",[["Bone",[["Object3D",[["Object3D",[]]]]]]]]]]]]]]]]]]]]]],["Bone",[["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]]]],["Bone",[["Bone",[["Bone",[["Bone",[["Object3D",[]]]]]]]]]]]],["SkinnedMesh",[]],["SkinnedMesh",[]]]]]],["PerspectiveCamera",[]]]]

(This is actually the same model as in the JSFiddle example, just re-exported from Blender and loaded a bit differently, I think.)

It doesn't look like there are any Mesh objects, or any objects that contain renderable geometry, except for the two SkinnedMeshes, however.

[rchee]

Same issue when I using SSAOPass. It looks like threejs cached a Program which not incolude #define USE_SKINNING #define BONE_TEXTURE and use it in randering Skinning Mash.

For my useage, I add below code here to temporarily fix the issue.

		if(material.type === "MeshNormalMaterial"){
			needsProgramChange = true 
		}