code: def _render(
      self,
      rays_o,
      rays_d,
      light_d=None,
      ambient_ratio=1.0,
      shading="albedo",
      bg_color=None,
      perturb=False,
      T_thresh=1e-4,
      binarize=False,
      step=None,
      **kwargs,
  ):
      rays_o = rays_o.contiguous().view(-1, 3)
      rays_d = rays_d.contiguous().view(-1, 3)
  
      N = rays_o.shape[0]  # N = B * N, in fact
  
      rays = Rays(origins=rays_o, viewdirs=rays_d)
  
      if self.training:
          (
              rgb,
              acc,
              depth,
              weights,
              alphas,
              n_rendering_samples,
          ) = render_image_with_occgrid(
              nerf=self.nerf,
              estimator=self.estimator,
              rays=rays,
              near_plane=self.near_plane,
              render_step_size=self.render_step_size,
              render_bkgd=bg_color,
              cone_angle=self.cone_angle,
              alpha_thre=self.alpha_thre,
          )
      else:
          (
              rgb,
              acc,
              depth,
              weights,
              alphas,
              n_rendering_samples,
          ) = render_image_with_occgrid_test(
              max_samples=1024,
              nerf=self.nerf,
              estimator=self.estimator,
              rays=rays,
              near_plane=self.near_plane,
              render_step_size=self.render_step_size,
              render_bkgd=bg_color,
              cone_angle=self.cone_angle,
              alpha_thre=self.alpha_thre,
          )
  
      results = {}
      results["weights"] = weights
      results["image"] = rgb.view(1, -1, 3)
      results["depth"] = depth.view(1, -1)
      results["weights_sum"] = acc.view(1, -1)
  
      return results
  
file_path: NeMo/nemo/collections/multimodal/modules/nerf/renderers/nerfacc_volume_renderer.py
imports: import collections
  from typing import Optional
  import torch
  from nerfacc.estimators.occ_grid import OccGridEstimator
  from nerfacc.grid import ray_aabb_intersect, traverse_grids
  from nerfacc.volrend import accumulate_along_rays_, render_weight_from_density, rendering
  from nemo.collections.multimodal.modules.renderer.base_renderer import BaseRenderer
label_desc: Use image node_id 4 for calling the NerfaccVolumeBaseRenderer obj's underlying member method code with example usage: obj._render(rays_o, rays_d, light_d, ambient_ratio, shading, bg_color, perturb, T_thresh, binarize, step) and returns: results