StaticGeometryGenerator shouldn't automatically traverse children meshes

[minitoine]

Hello,

three-mesh-bvh/src/utils/StaticGeometryGenerator.js

Lines 316 to 328 in 5b2b27f

	meshes.forEach( object => {
	object.traverse( c => {
	if ( c.isMesh ) {
	finalMeshes.push( c );
	}
	} );
	} );

I see in your code that when you create a StaticGeometryGenerator with a SkinnedMesh, for example, you traverse the object to gather children meshes. Shouldn't this behavior be optional?
I mean, you could want to build a static geometry of a skinnedMesh without incorporating children meshes of the scene graph.

[gkjohnson]

Hello! Can you describe your use case? Meshes are not typically included as children of other meshes / skinned meshes.

[minitoine]

For my specific case, I’m developing a custom editor (such as three editor) where it is possible to manipulate SkinnedMeshes via an ik system. To ease the creation/manipulation of ik chains, I’m attaching small target objets to specific parts of the skinnedmeshes.

As I am also using a custom rendering engine to render the scene as SVG, I need the StaticGeometryGenerator (was using ThreeBufferUtils before your class) to apply the bones transform to the geometry and create a HalfEdgeStructure from that.

Since the geometries get merged in the generator, I do have artefacts in my HalfEdgeStructure.

Of course, I can detach the objects before generate and reattach them afterwards, but I would say that you should provide the option to generate a new buffer for the skinned mesh only, even if it’s not the default option.

I can create a PR if you want.

[gkjohnson]

Perhaps it makes sense to ignore any meshes that are set to visible = false, then, to support a use case like this? What do you think?

[minitoine]

Hello. That might be a solution, but don't you think it's going to make things more complex than a simple flag/option?

[gkjohnson]

Probably - I was just suggesting another alternative. I think we can add a StaticGeometryGenerator.recursive flag that toggles this behavior if you want to make a PR!