Update app.py

app.py

@@ -53,11 +53,12 @@ For a mesh file `mesh.glb` and corresponding face mask `mask.npy`, prepare your
 import trimesh
 import numpy as np
 mesh = trimesh.load("mesh.glb", force="mesh")
+mask_npy = np.load("mask.npy")
 mesh_parts = []
 for part_id in np.unique(mask_npy):
     mesh_part = mesh.submesh([mask_npy == part_id], append=True)
     mesh_parts.append(mesh_part)
-mesh_parts = trimesh.Scene(mesh_parts).export(input_mesh.glb)
+mesh_parts = trimesh.Scene(mesh_parts).export("input_mesh.glb")
 ```
 The resulting **input_mesh.glb** is your prepared input for HoloPart.
 ### Step 2: Click the Decompose Parts button to begin the decomposition process.