Update trellis/utils/postprocessing_utils.py

trellis/utils/postprocessing_utils.py

@@ -453,24 +453,24 @@ def to_glb(
     )
     texture = Image.fromarray(texture)
 
-        # rotate mesh (from z-up to y-up)
+    # rotate mesh (from z-up to y-up)
     vertices = vertices @ np.array([[1, 0, 0], [0, 0, -1], [0, 1, 0]])
     
-    # OLD CODE (causes pale AR appearance):
-    # material = trimesh.visual.material.PBRMaterial(
-    #     roughnessFactor=1.0,
-    #     baseColorTexture=texture,
-    #     baseColorFactor=np.array([255, 255, 255, 255], dtype=np.uint8)
-    # )
-    
-    # NEW CODE (fixed - triggers Model Viewer to add IOR):
+    # Create material WITHOUT explicit factors (lets Model Viewer add IOR/clearcoat in USDZ)
     material = trimesh.visual.material.PBRMaterial(
         baseColorTexture=texture
     )
     
     mesh = trimesh.Trimesh(vertices, faces, visual=trimesh.visual.TextureVisuals(uv=uvs, material=material))
-    return mesh
     
+    # CRITICAL: Compute vertex normals - triggers Model Viewer to add ior/clearcoat to USDZ
+    # This fixes pale appearance in iOS AR!
+    mesh.vertex_normals  # Access triggers auto-computation if missing
+    
+    if verbose:
+        print(f"✅ Generated {len(mesh.vertex_normals)} vertex normals for iOS AR compatibility")
+    
+    return mesh
 
 
 def simplify_gs(