ungroup without removing

Questions
1

Is there a way to ungroup an object in a group but remain in the scene?

2

Sounds like a job for SceneUtils.detach().

2 Likes
3

solved, thanks.

// we pass to the function the child object of another object as a parameter.

function unGrupsinBorrar (ModelSelect) {


// we get the Id
var elId=ModelSelect.id;

// declare the object in a variable
var objetUngrup=scene.getObjectById(elId);

// we get the position
var laPosicion=(scene.getObjectById(elId)).getWorldPosition();

// we get the rotation
var laRotacion=(scene.getObjectById(elId)).getWorldRotation();

// we remove the object from the scene - it is not deleted because it is declared in the variable--
scene.remove(scene.getObjectById(elId));

// We add the object to the scene - it appears in the position (0,0,0) and rotation (0,0,0)
scene.add(objetUngrup);

// We recover the position
objetUngrup.position.copy(laPosicion);

// We recover the rotation
objetUngrup.rotation.copy(laRotacion);

// The object is now inserted as a child of the scene, with the same ID it had

}
4

You should consider the following to improve the performance of your code:

  • Every time you call .getWorldPosition() and .getWorldRotation(), you create for each call a new object of Vector3. To avoid this, apply a result object as a parameter.
var laPosicion = new THREE.Vector3();

function unGrupsinBorrar (ModelSelect) {

   var elId=ModelSelect.id;

   var objetUngrup=scene.getObjectById(elId); // only call this once and reuse objetUngrup

   objetUngrup.getWorldPosition( laPosicion );

   // ...
  • Also consider to work with matrixWorld directly. It simplifies your code and you don’t miss any transformations like scaling. Check out the source code of SceneUtils.detach() for more information.
1 Like
5

I needed to ungroup recursively and made this.

function flattenGroup(group, recursive) { // group can be the entire scene
	group.updateMatrixWorld();
	var again;

	do {
		again = false;

		group.children.slice().reverse().forEach(function(parent){

			parent.children.slice().reverse().forEach(function(child){

				again = true;

				parent.remove( child );
				child.applyMatrix( parent.matrix );
				group.add( child );
			});

		});

	} while (again && recursive);

	group.children.slice().reverse().forEach(function(child){

		if (child.type == 'Group'){

			if(child.children.length == 0){

				group.remove( child );

			} else{

				console.log("group still has children")
				
			}
		}
	});
}