Title
Accurate appearance preserving prefiltering for rendering displacement-mapped surfaces
Abstract
Prefiltering the reflectance of a displacement-mapped surface while preserving its overall appearance is challenging, as smoothing a displacement map causes complex changes of illumination effects such as shadowing-masking and interreflection. In this paper, we introduce a new method that prefilters displacement maps and BRDFs jointly and constructs SVBRDFs at reduced resolutions. These SVBRDFs preserve the appearance of the input models by capturing both shadowing-masking and interreflection effects. To express our appearance-preserving SVBRDFs efficiently, we leverage a new representation that involves spatially varying NDFs and a novel scaling function that accurately captures micro-scale changes of shadowing, masking, and interreflection effects. Further, we show that the 6D scaling function can be factorized into a 2D function of surface location and a 4D function of direction. By exploiting the smoothness of these functions, we develop a simple and efficient factorization method that does not require computing the full scaling function. The resulting functions can be represented at low resolutions (e.g., 42 for the spatial function and 154 for the angular function), leading to minimal additional storage. Our method generalizes well to different types of geometries beyond Gaussian surfaces. Models prefiltered using our approach at different scales can be combined to form mipmaps, allowing accurate and anti-aliased level-of-detail (LoD) rendering.
Year
DOI
Venue
2019
10.1145/3306346.3322936
ACM Transactions on Graphics (TOG)
Keywords
Field
DocType
global illumination, level of detail, multi-resolution, prefiltering
Computer vision,Level of detail,Global illumination,Artificial intelligence,Rendering (computer graphics),Mathematics
Journal
Volume
Issue
ISSN
38
4
0730-0301
Citations 
PageRank 
References 
0
0.34
0
Authors
4
Name
Order
Citations
PageRank
lifan wu192.49
Shuang Zhao235826.74
Ling-Qi Yan3127.99
Ravi Ramamoorthi44481237.21