Fix SparkPlug 3D preview, remove global loader overlay during generation, and fix empty scene hierarchy bug when transferring to Editor

src/pages/Editor.tsx

@@ -1026,6 +1026,51 @@ export default function Editor() {
               child.frustumCulled = false; // Prevent flickering on large models
             }
           });
+
+          setSceneObjects(prev => {
+            // If the scene already has objects, don't overwrite them
+            if (prev.length > 0) return prev;
+            
+            // Build default hierarchy for fresh imported models (like from SparkPlug)
+            const mainModelId = `model-${Date.now()}`;
+            const builtObjects: SceneObject[] = [
+              { 
+                id: mainModelId, 
+                name: modelInfo.name || 'Imported Model', 
+                type: 'model', 
+                parentId: null, 
+                visible: true,
+                transformProps: { position: [0, 0, 0], rotation: [0, 0, 0], scale: [1, 1, 1] }
+              }
+            ];
+            
+            let mIdx = 0;
+            object!.traverse((child) => {
+              if (child instanceof THREE.Mesh) {
+                const meshId = `mesh-${mIdx++}`;
+                const material = Array.isArray(child.material) ? child.material[0] : child.material;
+                const mProps = { ...globalMaterialProps };
+                
+                if (material) {
+                  if (material.color) mProps.color = `#${material.color.getHexString()}`;
+                  if (material.roughness !== undefined) mProps.roughness = material.roughness;
+                  if (material.metalness !== undefined) mProps.metalness = material.metalness;
+                  if (material.opacity !== undefined) mProps.opacity = material.opacity;
+                }
+                
+                builtObjects.push({
+                  id: meshId,
+                  name: child.name || `Mesh ${meshId.slice(0, 4)}`,
+                  type: 'mesh',
+                  parentId: mainModelId,
+                  visible: true,
+                  materialProps: mProps
+                });
+              }
+            });
+            return builtObjects;
+          });
+
           setLoadedModel(object);
           setBlobURLs(prev => [...prev, url]);
         }

src/pages/SparkPlug.tsx

@@ -1,7 +1,14 @@
-import React, { useState } from 'react';
+import React, { useState, Suspense } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { Sparkles, Upload, FileText, Image as ImageIcon, Box, Check, Loader2, ArrowRight, RefreshCw, ChevronLeft } from 'lucide-react';
 import { api } from '../lib/api';
+import { Canvas } from '@react-three/fiber';
+import { OrbitControls, Stage, useGLTF } from '@react-three/drei';
+
+function ModelPreview({ url }: { url: string }) {
+  const { scene } = useGLTF(url);
+  return <primitive object={scene} />;
+}
 
 const STEPS = [
   { id: 1, title: 'Upload PDF', icon: Upload },
@@ -115,6 +122,7 @@ export default function SparkPlug() {
       
       // Immediately move to step 4 to show the progress bar
       setCurrentStep(4);
+      setIsLoading(false);
       
       // Poll Meshy status
       let isDone = false;
@@ -131,6 +139,7 @@ export default function SparkPlug() {
         }
         
         if (status === 'SUCCEEDED') {
+          setModelProgress(100);
           setGeneratedGlbUrl(model_urls.glb);
           isDone = true;
           // The step is already 4, user just clicks "Open in Editor" when progress >= 100
@@ -163,20 +172,19 @@ export default function SparkPlug() {
       
       // Create project and save with model injected into scene_data
       const res = await api.saveProject({
-        name: "Spark Plug Output",
+        name: pdfFile?.name ? pdfFile.name.replace(/\.[^/.]+$/, "") : "Spark Plug Output",
         scene_data: {
-          objects: [
-            {
-              id: "model_" + Date.now(),
-              type: "model",
+          sceneObjects: [],
+          modelData: {
             name: "Generated Product Model",
-              visible: true,
-              position: [0, 0, 0],
-              rotation: [0, 0, 0],
-              scale: [1, 1, 1],
-              url: generatedGlbUrl
-            }
-          ]
+            data: generatedGlbUrl,
+            extension: "glb"
+          },
+          backgroundColor: '#444444',
+          backgroundType: 'color',
+          envPreset: 'studio',
+          lightProps: { intensity: 1, color: '#ffffff', shadowBias: -0.0005, shadowRadius: 4 },
+          groundProps: { showShadow: true, shadowIntensity: 0.4, shadowRotation: 0, shadowSoftness: 0.5, shadowLength: 10 }
         }
       });
       if (res.id) {
@@ -367,7 +375,9 @@ export default function SparkPlug() {
           )}
 
           {currentStep === 4 && (
-            <div className="flex-1 flex flex-col items-center justify-center gap-6 animate-in fade-in slide-in-from-right-8 duration-300">
+            <div className="flex-1 flex flex-col items-center justify-center gap-6 animate-in fade-in slide-in-from-right-8 duration-300 w-full">
+              {modelProgress < 100 ? (
+                <>
                   <div className="w-24 h-24 rounded-full border-4 border-zinc-800 border-t-amber-500 animate-spin flex items-center justify-center">
                     <Box size={32} className="text-zinc-500 animate-pulse" />
                   </div>
@@ -375,7 +385,7 @@ export default function SparkPlug() {
                   <div className="text-center w-full max-w-sm">
                     <h2 className="text-xl font-bold mb-2">Generating 3D Model...</h2>
                     <p className="text-sm text-zinc-400 mb-6">
-                  Meshy is constructing the model based on the Nano Banana concept images.
+                      Meshy is constructing the model based on the concept images.
                     </p>
 
                     <div className="w-full bg-zinc-950 rounded-full h-3 overflow-hidden">
@@ -386,16 +396,32 @@ export default function SparkPlug() {
                     </div>
                     <div className="text-xs font-bold text-amber-500 mt-2">{modelProgress}% Complete</div>
                   </div>
-
-              {modelProgress >= 100 && (
+                </>
+              ) : (
+                <div className="w-full h-[400px] bg-zinc-900 rounded-xl overflow-hidden relative border border-zinc-800 flex flex-col items-center justify-center">
+                  {generatedGlbUrl ? (
+                    <Canvas shadows dpr={[1, 2]} camera={{ position: [0, 0, 4], fov: 45 }}>
+                      <Suspense fallback={null}>
+                        <Stage environment="studio" intensity={0.5}>
+                          <ModelPreview url={generatedGlbUrl} />
+                        </Stage>
+                      </Suspense>
+                      <OrbitControls autoRotate />
+                    </Canvas>
+                  ) : (
+                    <div className="text-zinc-500">Failed to load preview</div>
+                  )}
+                  <div className="absolute bottom-6 flex justify-center w-full z-10 pointer-events-none">
                     <button 
                       onClick={processStep4}
                       disabled={isLoading}
-                  className="mt-6 flex items-center gap-2 bg-amber-500 hover:bg-amber-600 text-black px-8 py-3 rounded-xl font-bold transition-all disabled:opacity-50 animate-in fade-in slide-in-from-bottom-4"
+                      className="pointer-events-auto flex items-center gap-2 bg-amber-500 hover:bg-amber-600 text-black px-8 py-3 rounded-xl font-bold transition-all shadow-xl disabled:opacity-50 animate-in fade-in slide-in-from-bottom-4"
                     >
                       {isLoading ? <Loader2 className="animate-spin" size={18} /> : <Check size={18} />}
                       Open in Editor
                     </button>
+                  </div>
+                </div>
               )}
             </div>
           )}