diff --git a/20210129/demo/js/loader.js b/20210129/demo/js/loader.js
index d422eda..dcf007d 100644
--- a/20210129/demo/js/loader.js
+++ b/20210129/demo/js/loader.js
@@ -96,7 +96,7 @@ BIMLoader = function(json)
         var edges = new THREE.EdgesGeometry(mesh.geometry);
         var line = new THREE.LineSegments(edges, new THREE.LineBasicMaterial({color: 0xff0000}));
             
-        obj.add(mesh);
+        obj.add(mesh.clone());
         obj.add(line);
     }
 }
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