Fix modelData saving and error catching

src/pages/Editor.tsx

@@ -706,22 +706,16 @@ export default function Editor() {
       const zipObj: Record<string, Uint8Array> = {};
 
       if (sceneData.modelData && sceneData.modelData.data && typeof sceneData.modelData.data === 'string') {
-        if (sceneData.modelData.data.startsWith('data:')) {
-          const dataUrl = sceneData.modelData.data;
-          const base64 = dataUrl.split(',')[1];
-          const binaryStr = atob(base64);
-          const len = binaryStr.length;
-          const bytes = new Uint8Array(len);
-          for (let i = 0; i < len; i++) {
-            bytes[i] = binaryStr.charCodeAt(i);
-          }
-          zipObj['model.glb'] = bytes;
-          sceneData.modelData.data = 'model.glb';
-        } else if (sceneData.modelData.data.startsWith('blob:') || sceneData.modelData.data.startsWith('http')) {
-           const res = await fetch(sceneData.modelData.data);
-           const buf = await res.arrayBuffer();
-           zipObj['model.glb'] = new Uint8Array(buf);
-           sceneData.modelData.data = 'model.glb';
+        if (sceneData.modelData.data.startsWith('data:') || sceneData.modelData.data.startsWith('blob:') || sceneData.modelData.data.startsWith('http')) {
+           try {
+             const res = await fetch(sceneData.modelData.data);
+             const buf = await res.arrayBuffer();
+             zipObj['model.glb'] = new Uint8Array(buf);
+             sceneData.modelData.data = 'model.glb';
+           } catch (fetchErr) {
+             console.error("Failed to fetch modelData for zipping", fetchErr);
+             throw fetchErr;
+           }
         }
       }
 
@@ -989,7 +983,14 @@ export default function Editor() {
     setIsLoading(true);
     setImportStatus("Restoring model...");
     try {
+      if (modelInfo.data === 'model.glb') {
+        throw new Error("Model data is missing from the project file.");
+      }
+      
       const response = await fetch(modelInfo.data);
+      if (!response.ok) {
+        throw new Error(`Failed to fetch model: ${response.statusText}`);
+      }
       const blob = await response.blob();
       const url = URL.createObjectURL(blob);
       
@@ -1074,11 +1075,12 @@ export default function Editor() {
           setLoadedModel(object);
           setBlobURLs(prev => [...prev, url]);
         }
-      setIsLoading(false);
-    } catch (error) {
-      console.error('Error re-importing model:', error);
-      setIsLoading(false);
-    }
+        setIsLoading(false);
+      } catch (error: any) {
+        console.error('Error re-importing model:', error);
+        setImportError(error.message || "Failed to load model from project file.");
+        setIsLoading(false);
+      }
   };
 
   const handleTextureUpload = (event: React.ChangeEvent<HTMLInputElement>, type: 'map' | 'normalMap' | 'specularMap' | 'alphaMap' = 'map') => {