code: def _figure_eight_knot(t: torch.Tensor, z_scale: float = 0.5):
      x = (2 + (2 * t).cos()) * (3 * t).cos()
      y = (2 + (2 * t).cos()) * (3 * t).sin()
      z = (4 * t).sin() * z_scale
      return torch.stack((x, y, z), dim=-1)
  
file_path: pytorch3d/projects/nerf/nerf/eval_video_utils.py
imports: import math
  from typing import Tuple
  import torch
  from pytorch3d.renderer import look_at_view_transform, PerspectiveCameras
  from torch.utils.data.dataset import Dataset
label_desc: Use image node_id 2 for calling a global function with example usage: _figure_eight_knot(t, z_scale) and returns: torch