code: def clip_faces(meshes):
      verts_packed = meshes.verts_packed()
      faces_packed = meshes.faces_packed()
      face_verts = verts_packed[faces_packed]
      mesh_to_face_first_idx = meshes.mesh_to_faces_packed_first_idx()
      num_faces_per_mesh = meshes.num_faces_per_mesh()
  
      frustum = ClipFrustum(
          left=-1,
          right=1,
          top=-1,
          bottom=1,
          # In the unit tests for each case below the triangles are asummed
          #  to have already been projected onto the image plane.
          perspective_correct=False,
          z_clip_value=1e-2,
          cull=True,  # Cull to frustrum
      )
  
      clipped_faces = clip_faces(
          face_verts,
          mesh_to_face_first_idx,
          num_faces_per_mesh,
          frustum,
      )
      return clipped_faces
  
imports: import unittest
  import imageio
  import numpy
  import torch
  from pytorch3d.io import save_obj
  from pytorch3d.renderer.cameras import FoVPerspectiveCameras, look_at_view_transform, PerspectiveCameras
  from pytorch3d.renderer.lighting import PointLights
  from pytorch3d.renderer.mesh import clip_faces, ClipFrustum, convert_clipped_rasterization_to_original_faces, TexturesUV
  from pytorch3d.renderer.mesh.rasterize_meshes import _RasterizeFaceVerts
  from pytorch3d.renderer.mesh.rasterizer import MeshRasterizer, RasterizationSettings
  from pytorch3d.renderer.mesh.renderer import MeshRenderer
  from pytorch3d.renderer.mesh.shader import SoftPhongShader
  from pytorch3d.renderer.mesh.textures import TexturesVertex
  from pytorch3d.structures.meshes import Meshes
  from pytorch3d.utils import torus
  from .common_testing import get_tests_dir, load_rgb_image, TestCaseMixin
label_desc: Use image node_id 3 for calling the TestRenderMeshesClipping obj's underlying member method code with example usage: obj.clip_faces(meshes) and returns: clipped_faces