code: def export_to_ply(mesh, output_ply_path: str = None):
      """
      Write a PLY file for a mesh.
      """
      if output_ply_path is None:
          output_ply_path = tempfile.NamedTemporaryFile(
              suffix=".ply"
          ).name
  
      coords = mesh.verts.detach().cpu().numpy()
      faces = mesh.faces.cpu().numpy()
      rgb = np.stack(
          [
              mesh.vertex_channels[x].detach().cpu().numpy()
              for x in "RGB"
          ],
          axis=1,
      )
  
      with buffered_writer(open(output_ply_path, "wb")) as f:
          f.write(b"ply\n")
          f.write(b"format binary_little_endian 1.0\n")
          f.write(bytes(f"element vertex {len(coords)}\n", "ascii"))
          f.write(b"property float x\n")
          f.write(b"property float y\n")
          f.write(b"property float z\n")
          if rgb is not None:
              f.write(b"property uchar red\n")
              f.write(b"property uchar green\n")
              f.write(b"property uchar blue\n")
          if faces is not None:
              f.write(bytes(f"element face {len(faces)}\n", "ascii"))
              f.write(b"property list uchar int vertex_index\n")
          f.write(b"end_header\n")
  
          if rgb is not None:
              rgb = (rgb * 255.499).round().astype(int)
              vertices = [
                  (*coord, *rgb)
                  for coord, rgb in zip(
                      coords.tolist(),
                      rgb.tolist(),
                  )
              ]
              format = struct.Struct("<3f3B")
              for item in vertices:
                  f.write(format.pack(*item))
          else:
              format = struct.Struct("<3f")
              for vertex in coords.tolist():
                  f.write(format.pack(*vertex))
  
          if faces is not None:
              format = struct.Struct("<B3I")
              for tri in faces.tolist():
                  f.write(format.pack(len(tri), *tri))
  
      return output_ply_path
  
imports: import functools
  import importlib
  import inspect
  import io
  import logging
  import multiprocessing
  import os
  import random
  import re
  import struct
  import sys
  import tempfile
  import time
  import unittest
  import urllib.parse
  from contextlib import contextmanager
  from distutils.util import strtobool
  from io import BytesIO, StringIO
  from pathlib import Path
  from typing import List, Optional, Union
  import numpy
  import PIL.Image
  import PIL.ImageOps
  import requests
  from numpy.linalg import norm
  from packaging import version
  from .import_utils import BACKENDS_MAPPING, is_compel_available, is_flax_available, is_note_seq_available, is_onnx_available, is_opencv_available, is_peft_available, is_torch_available, is_torch_version, is_torchsde_available, is_transformers_available
  from .logging import get_logger
label_desc: Use image node_id 27 for calling a global function with example usage: export_to_ply(mesh, output_ply_path) and returns: output_ply_path