[Solved] What is Object3D type used for?

mkarnicki · April 22, 2018, 3:23pm

Hi. I would like to understand what exactly is Object3D type used for?

I have looked at the doc page of Object3D, but there’s no mention of it.

I’m extending Object3D (and Mesh) to create my own subtypes of objects and would like to understand if it’s safe to overwrite that value, just like SkinnedMesh does for instance?

Thanks

Mugen87 · April 22, 2018, 6:04pm

It is relevant for serialization/deserialization. ObjectLoader uses this property at various places, e,g

github.com

mrdoob/three.js/blob/3aff5401695bbcc883fd0e13f24e78fc430a1ea1/src/loaders/ObjectLoader.js#L636


			if ( materials[ name ] === undefined ) {


				console.warn( 'THREE.ObjectLoader: Undefined material', name );


			}


			return materials[ name ];


		}


		switch ( data.type ) {


			case 'Scene':


				object = new Scene();


				if ( data.background !== undefined ) {


					if ( Number.isInteger( data.background ) ) {


						object.background = new Color( data.background );

mkarnicki · April 22, 2018, 6:20pm

Perfect, thank you! I guess I should stay away from touching it then

Mugen87 · April 22, 2018, 6:32pm

If you don’t need serialization/deserialization, just ignore it.

mkarnicki · April 22, 2018, 6:45pm

Thanks @Mugen87 ! I think I’ll actually try making use of serialization. I’m working on a diagramming tool and using THREE for the graphics. I initially thought I’d have to come up with my own JSON format and then found THREE already has that. So with little luck I should be able to leverage that for project saving/restoring \o/

looeee · April 23, 2018, 2:05am

It should probably be in the docs - I added this in for most other objects but but must have missed this one.

By the way, there are other times you might want to use the isXXX properties.In the FBXLoader example isMesh is used enable shadows for any child meshes:

github.com

mrdoob/three.js/blob/master/examples/webgl_loader_fbx.html#L113-L122


					object.traverse( function ( child ) {


						if ( child.isMesh ) {


							child.castShadow = true;
							child.receiveShadow = true;


						}


					} );

mkarnicki · April 23, 2018, 7:46am

Hi @looeee ,

Aren’t these two things different though? To be precise, I was asking about the objectInstance.type member field.

Have a nice day!

looeee · April 23, 2018, 8:23am

Oh, you’re correct. Sorry!

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[Solved] What is Object3D type used for?

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