diff --git a/src/document/scene-document-validation.ts b/src/document/scene-document-validation.ts
index 91b512e9..08964948 100644
--- a/src/document/scene-document-validation.ts
+++ b/src/document/scene-document-validation.ts
@@ -8540,6 +8540,7 @@ export function validateSceneDocument(
     }
 
     registerAuthoredId(material.id, path, seenIds, diagnostics);
+    validateMaterialDef(material, path, document.assets, diagnostics);
   }
 
   for (const [assetKey, asset] of Object.entries(document.assets)) {