Return first geometryBuffer if no best batch found

CHANGES.md

@@ -8,6 +8,10 @@
 
 - Added `enableVerticalExaggeration` option to models. Set this value to `false` to prevent model exaggeration when `Scene.verticalExaggeration` is set to a value other than `1.0`. [#12141](https://github.com/CesiumGS/cesium/pull/12141)
 
+##### Fixes :wrench:
+
+- Use first geometryBuffer if no best match found in I3SNode [#12132](https://github.com/CesiumGS/cesium/pull/12132)
+
 ### 1.121.1 - 2024-09-04
 
 This is an npm-only release to extra source maps included in 1.121

CONTRIBUTORS.md

@@ -407,5 +407,6 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 - [Vladislav Yunev](https://github.com/YunVlad)
 - [Levi Montgomery](https://github.com/Levi-Montgomery)
 - [Brandon Berisford](https://github.com/BeyondBelief96)
+- [Lawrence Owen](https://github.com/ljowen)
 - [Adam Wirth](https://https://github.com/adamwirth)
 - [Javier Sanchez](https://github.com/jvrjsanchez)

packages/engine/Source/Scene/I3SLayer.js

@@ -291,9 +291,15 @@ I3SLayer.prototype._findBestGeometryBuffers = function (
         };
       }
     }
+    // If no match found return first geometryBuffer
+    if (defined(geometryDefinition[0])) {
+      return {
+        bufferIndex: 0,
+        definition: geometryDefinition,
+        geometryBufferInfo: geometryDefinition[0],
+      };
+    }
   }
-
-  return 0;
 };
 
 /**

packages/engine/Source/Scene/I3SNode.js

@@ -219,7 +219,7 @@ I3SNode.prototype.load = async function () {
     const uriIndex = node.mesh.geometry.resource;
     uri = `../${uriIndex}/`;
   }
-  if (defined(uri)) {
+  if (defined(uri) && defined(that._parent.resource)) {
     that._resource = that._parent.resource.getDerivedResource({ url: uri });
   }