diff --git a/src/components/three/ModelViewer.tsx b/src/components/three/ModelViewer.tsx
index e2d08c6..8725376 100644
--- a/src/components/three/ModelViewer.tsx
+++ b/src/components/three/ModelViewer.tsx
@@ -123,22 +123,33 @@ function GLBModel({ sceneModel, isActive }: { sceneModel: SceneModel; isActive:
 
   if (!sceneModel.visible) return null;
 
+  // Determine dominant local axis of the model (longest bbox side) for axial roll
+  const dominantAxis: 'x' | 'y' | 'z' =
+    modelInfo.size.x >= modelInfo.size.y && modelInfo.size.x >= modelInfo.size.z
+      ? 'x'
+      : modelInfo.size.y >= modelInfo.size.z
+      ? 'y'
+      : 'z';
+
   return (
     <group
       scale={[renderFactor, renderFactor, renderFactor]}
       onClick={(e) => { e.stopPropagation(); setActive(sceneModel.id); }}
+      userData={{ modelId: sceneModel.id, dominantAxis }}
     >
-      <group
-        ref={ref}
-        position={[
-          -modelInfo.center.x + fineTuning.posX,
-          -modelInfo.center.y + fineTuning.posY,
-          -modelInfo.center.z + fineTuning.posZ,
-        ]}
-        rotation={[rotXRad, rotYRad, rotZRad]}
-        scale={[s, s, s]}
-      >
-        <primitive object={scene} />
+      {/* Translation */}
+      <group position={[fineTuning.posX, fineTuning.posY, fineTuning.posZ]}>
+        {/* Rotation + scale around the geometry center */}
+        <group
+          ref={ref}
+          rotation={[rotXRad, rotYRad, rotZRad]}
+          scale={[s, s, s]}
+        >
+          {/* Shift geometry so its center sits at the parent's origin (pivot = center) */}
+          <group position={[-modelInfo.center.x, -modelInfo.center.y, -modelInfo.center.z]}>
+            <primitive object={scene} />
+          </group>
+        </group>
       </group>
     </group>
   );