requested changes

src/three/DebugTilesRenderer.js

@@ -191,7 +191,7 @@ export class DebugTilesRenderer extends TilesRenderer {
 		}
 
 		let maxDistance = - 1;
-		if ( this.maxDebugDistance === - 1 ) {
+		if ( this.maxDebugDistance === - 1 && this.root.cached.sphere ) {
 
 			maxDistance = this.root.cached.sphere.radius;
 

src/three/TilesRenderer.js

@@ -525,14 +525,6 @@ export class TilesRenderer extends TilesRendererBase {
 			sphere.radius = data[ 3 ];
 			sphere.applyMatrix4( transform );
 
-		} else if ( 'box' in tile.boundingVolume ) {
-
-			const data = tile.boundingVolume.box;
-			sphere = new Sphere();
-			box.getBoundingSphere( sphere );
-			sphere.center.set( data[ 0 ], data[ 1 ], data[ 2 ] );
-			sphere.applyMatrix4( transform );
-
 		}
 
 		const region = null;