sphereIntersect( sphere ) {

		_sphere.copy( sphere );

		const triangles = [];
		let result, hit = false;

		this.getSphereTriangles( sphere, triangles );

		for ( let i = 0; i < triangles.length; i ++ ) {

			if ( result = this.triangleSphereIntersect( _sphere, triangles[ i ] ) ) {

				hit = true;

				_sphere.center.add( result.normal.multiplyScalar( result.depth ) );

			}

		}

		if ( hit ) {

			const collisionVector = _sphere.center.clone().sub( sphere.center );
			const depth = collisionVector.length();

			return { normal: collisionVector.normalize(), depth: depth };

		}

		return false;

	}
Performs a bounding sphere intersection test with this Octree.

@param {Sphere} sphere - The bounding sphere to test.
@return {Object|boolean} The intersection object. If no intersection
is detected, the method returns `false`.