Efficient Space Skipping and Adaptive Sampling of Unstructured Volumes Using Hardware Accelerated Ray Tracing

Nate Morrical, Will Usher, Ingo Wald and Valerio Pascucci

In IEEE VIS Short Papers, 2019.

Fig. 1: Performance improvement of our method on the 278 million tetrahedra Japan Earthquake data set. (a) A reference volume ray marcher without our method, at 0.9 FPS (1024^2 pixels) on an NVIDIA RTX 8000 GPU. (b) A heat map of relative cost per-pixel in (a). (c) and (d), the same, but now with our space skipping and adaptive sampling method, running at 7 FPS (7× faster).


Sample based ray marching is an effective method for direct volume rendering of unstructured meshes. However, sampling such meshes remains expensive, and strategies to reduce the number of samples taken have received relatively little attention. In this paper, we introduce a method for rendering unstructured meshes using a combination of a coarse spatial acceleration structure and hardware-accelerated ray tracing. Our approach enables efficient empty space skipping and adaptive sampling of unstructured meshes, and outperforms a reference ray marcher by up to 7×.


  title = {Efficient {Space} {Skipping} and {Adaptive} {Sampling} of {Unstructured}
      {Volumes} {Using} {Hardware} {Accelerated} {Ray} {Tracing}},
  booktitle = {IEEE VIS 2019 - Short Papers},
  author = {Morrical, Nate, and Usher, Will and Wald, Ingo, and Pascucci, Valerio},
  year = {2019}