frame name fixed

src/pixel3dmm/tracking/tracker.py

@@ -1288,7 +1288,7 @@ class Tracker(object):
 
                 # --- export the posed mesh, using the correct face indices field ---
                 os.makedirs(self.mesh_folder, exist_ok=True)
-                frame_id = str(self.frame).zfill(5)
+                frame_id = str(0).zfill(5)
                 ply_path = os.path.join(self.mesh_folder, f"{frame_id}.ply")
 
                 # pull out the face index tensor