Scalable Appearance Filtering for Complex Lighting Effects
Luis E. Gamboa, Jean-Philippe Guertin, Derek Nowrouzezahrai
ACM Transactions on Graphics
Presented at SIGGRAPH Asia 2018

Abstract
Realistic rendering with materials that exhibit high-frequency spatial variation remains a challenge, as eliminating spatial and temporal aliasing requires prohibitively high sampling rates. Recent work has made the problem more tractable, however existing methods remain prohibitively expensive when using large environmental lights and/or (correctly filtered) global illumination. We present an appearance model with explicit high-frequency micro-normal variation, and a filtering approach that scales to multi-dimensional shading integrals. By combining a novel and compact half-vector histogram scheme with a directional basis expansion, we accurately compute the integral of filtered high-frequency reflectance over large lights with angularly varying emission. Our approach is scalable, rendering images indistinguishable from ground truth at over 10x the speed of the state-of-the-art and with only 15% the memory footprint. When filtering appearance with global illumination, we outperform the state-of-the-art by ~30x.

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Official (ACM DL) version

@article{Gamboa:2018:SAF:3272127.3275058,
  author = {Gamboa, Luis E. and Guertin, Jean-Philippe and Nowrouzezahrai, Derek},
  title = {Scalable Appearance Filtering for Complex Lighting Effects},
  journal = {ACM Trans. Graph.},
  issue_date = {November 2018},
  volume = {37},
  number = {6},
  month = dec,
  year = {2018},
  issn = {0730-0301},
  pages = {277:1--277:13},
  articleno = {277},
  numpages = {13},
  url = {http://doi.acm.org/10.1145/3272127.3275058},
  doi = {10.1145/3272127.3275058},
  acmid = {3275058},
  publisher = {ACM},
  address = {New York, NY, USA},
  keywords = {glints, normal maps, spherical harmonics, summed area tables},
}