Fix performance bug with many tilesets

CHANGES.md

@@ -10,8 +10,9 @@
 
 ##### Fixes :wrench:
 
-- Fixes issue with `BingMapsImageryProvider` where given culture option is ineffective [#11695](https://github.com/CesiumGS/cesium/issues/11695)
+- Fixed issue with `BingMapsImageryProvider` where given culture option is ineffective [#11695](https://github.com/CesiumGS/cesium/issues/11695)
 - Fixed a bug where dynamic geometries caused the Scene to continuously render when running in requestRenderMode [#6631](https://github.com/CesiumGS/cesium/issues/6631)
+- Fixed a bug with performance in scenes with multiple tilesets [#11878](https://github.com/CesiumGS/cesium/pull/11878)
 - Fixes issue with PolygonGeometry uvs are improperly computed [#11767](https://github.com/CesiumGS/cesium/issues/11767)
 - Fixed voxel rendering bugs for non-spherical ellipsoid shapes [#11848](https://github.com/CesiumGS/cesium/pull/11848)
 

packages/engine/Source/Scene/Cesium3DTileset.js

@@ -2638,6 +2638,10 @@ const scratchUpdateHeightCartographic = new Cartographic();
 const scratchUpdateHeightCartographic2 = new Cartographic();
 const scratchUpdateHeightCartesian = new Cartesian3();
 function processUpdateHeight(tileset, tile, frameState) {
+  if (!tileset.enableCollision || !tileset.show) {
+    return;
+  }
+
   const heightCallbackData = tileset._addHeightCallbacks;
   const boundingSphere = tile.boundingSphere;