try now

app.py

@@ -119,14 +119,12 @@ def generate_3D(input, model_name='base1B', guidance_scale=3.0, grid_size=128):
     set_state('Converting to mesh...')
 
     uniqid = uuid.uuid4()
-    file_path = f'/tmp/mesh-{uniqid}.npz'
-
-    print(file_path)
-    pc.save(file_path)
+    file_path = f'/tmp/{uniqid}.ply'
+    save_ply(pc, file_path)
 
     set_state('')
 
-    return file_path, create_gif(pc), gr.update(value=['/tmp/mesh.ply'], visible=True)
+    return file_path, create_gif(pc), gr.update(value=[file_path], visible=True)
 
 def prepare_img(img):
 
@@ -150,6 +148,11 @@ def ply_to_glb(ply_file, glb_file):
 
     return glb_file
 
+def save_ply(pc, file_name):
+    # Produce a mesh (with vertex colors)
+    with open(file_name, 'wb') as f:
+        pc.write_ply(f)
+
 
 def create_gif(pc):
     fig = plt.figure(facecolor='black', figsize=(4, 4))