Add `onDisposeModel` function

src/three/TilesRenderer.js

@@ -83,6 +83,7 @@ export class TilesRenderer extends TilesRendererBase {
 		this._autoDisableRendererCulling = true;
 
 		this.onLoadModel = null;
+		this.onDisposeModel = null;
 
 	}
 
@@ -621,6 +622,12 @@ export class TilesRenderer extends TilesRendererBase {
 
 			}
 
+			if ( this.onDisposeModel ) {
+
+				this.onDisposeModel( cached.scene, tile );
+
+			}
+
 			cached.scene = null;
 			cached.materials = null;
 			cached.textures = null;