Preserving Realism in real-time Rendering of Bidirectional Texture Functions Jan Meseth, Gero Müller, Jan Meseth, Gero Müller, Reinhard Klein Reinhard Klein Bonn University Bonn University Computer Graphics Group Computer Graphics Group
Dec 18, 2015
Preserving Realism in real-time Rendering of
Bidirectional Texture Functions
Preserving Realism in real-time Rendering of
Bidirectional Texture Functions
Jan Meseth, Gero Müller, Jan Meseth, Gero Müller,
Reinhard KleinReinhard Klein
Bonn UniversityBonn University
Computer Graphics GroupComputer Graphics Group
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
MotivationMotivationMotivationMotivation
Hiqh-quality rendering in real-timeHiqh-quality rendering in real-time
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
MotivationMotivationMotivationMotivation
Current real-time applications:Current real-time applications: triangular modelstriangular models simple materials simple materials
TexturesTextures Bump MappingBump Mapping Displacement Displacement
MappingMapping
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
MotivationMotivationMotivationMotivation
Our approachOur approach more accurate material representationmore accurate material representation Real-time renderingReal-time rendering
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Problem DescriptionProblem DescriptionProblem DescriptionProblem Description
Real-world materials:Real-world materials: complex reflectance behavior (pointwise BRDF)complex reflectance behavior (pointwise BRDF) mesostructure with highly complicated self-mesostructure with highly complicated self-
occlusion, interreflection and self-shadowingocclusion, interreflection and self-shadowing changing perceived normalchanging perceived normal
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Previous WorkPrevious WorkPrevious WorkPrevious Work
BTF representation by DanaBTF representation by Dana
( , , ) ( , , , , , )l l v vBTF x l v BTF x y
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Previous WorkPrevious WorkPrevious WorkPrevious Work
Efficient Rendering of Spatial Bi-directional Efficient Rendering of Spatial Bi-directional Reflectance Distribution FunctionsReflectance Distribution FunctionsMcAllister, Lastra, Heidrich, Graphics Hardware 2002McAllister, Lastra, Heidrich, Graphics Hardware 2002
, , , ,( , , ) ,d x s x i x ii
BTF x l v L l v
0 0
, , , 0 0
0 0
i
i
i
N
x x
i x y z y y
zz
C l
L l v v v v C l
lC
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Previous WorkPrevious WorkPrevious WorkPrevious Work
Efficient Rendering of Spatial Bi-directional Efficient Rendering of Spatial Bi-directional Reflectance Distribution FunctionsReflectance Distribution FunctionsMcAllister, Lastra, Heidrich, Graphics Hardware 2002McAllister, Lastra, Heidrich, Graphics Hardware 2002
Rendering in real-time Rendering in real-time Good results for simple Good results for simple materialsmaterialsView-dependent effects View-dependent effects require many lobesrequire many lobesInsufficient for materials Insufficient for materials with high depth variationwith high depth variation
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Previous WorkPrevious WorkPrevious WorkPrevious Work
Efficient Cloth Modeling and RenderingEfficient Cloth Modeling and RenderingDaubert, Lensch, Heidrich, Seidel, Rendering Workshop 2001Daubert, Lensch, Heidrich, Seidel, Rendering Workshop 2001
,( , , ) , ,z i xi
BTF x l v T x v l L l v
view-dependentshadowing andmasking term
area fore-shortening
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Previous WorkPrevious WorkPrevious WorkPrevious Work
Efficient Cloth Modeling and RenderingEfficient Cloth Modeling and RenderingDaubert, Lensch, Heidrich, Seidel, Rendering Workshop 2001Daubert, Lensch, Heidrich, Seidel, Rendering Workshop 2001
view-dependent occlusion factorview-dependent occlusion factor evaluated per color channelevaluated per color channel change of perceived normal restrictedchange of perceived normal restricted based on synthesized materialsbased on synthesized materials
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Previous WorkPrevious WorkPrevious WorkPrevious Work
Towards Interactive Bump Mapping with Towards Interactive Bump Mapping with Anisotropic Shift-Variant BRDFsAnisotropic Shift-Variant BRDFsKautz, Seidel, Graphics Hardware 2000Kautz, Seidel, Graphics Hardware 2000
Fast, Arbitrary BRDF Shading for Low-Fast, Arbitrary BRDF Shading for Low-Frequency Lighting Using Spherical Frequency Lighting Using Spherical HarmonicsHarmonicsKautz, Sloan, Snyder, Rendering Workshop 2002Kautz, Sloan, Snyder, Rendering Workshop 2002
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Our ApproachOur ApproachOur ApproachOur Approach
truly view-dependent truly view-dependent perceived normalperceived normal reflectance propertiesreflectance properties
minimize approximation errorminimize approximation errorsuitable for real-time renderingsuitable for real-time rendering
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Data AnalysisData AnalysisData AnalysisData Analysis
Fitting Lafortune lobes to the entire BTF data for one Texel
Fitting a Reflectance Field to the BTF data for one pixel
Energy plot for one Texel of the Corduroy Data Set
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Reflectance FieldReflectance FieldReflectance FieldReflectance Field
describes intensity of surface point for describes intensity of surface point for varying light and fixed view directionvarying light and fixed view direction
good approximation by lobe-like modelgood approximation by lobe-like model
,
, , ,, , ,
v iN x
v v i v i v ii
RF x l a x b x c x l
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
BTF RenderingBTF RenderingBTF RenderingBTF Rendering
Preprocessing:Preprocessing:1.1. fit Reflectance Fields fit Reflectance Fields RFRFvivi for various view for various view
directions directions vvii
Runtime:Runtime:1.1. determine current view direction determine current view direction vv
2.2. select closest view directions from select closest view directions from {v{vii}}
3.3. compute color according to compute color according to RFRFvivi
4.4. interpolate between individual resultsinterpolate between individual results
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
BTF RenderingBTF RenderingBTF RenderingBTF Rendering
Storage requirements:Storage requirements: stack of floating point texturesstack of floating point textures about 400 MB per materialabout 400 MB per material
employ BTF synthesis algorithmemploy BTF synthesis algorithmstore indices instead of color valuesstore indices instead of color valuesreduces storage to about 25 MB per materialreduces storage to about 25 MB per material
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
ResultsResultsResultsResults
Textures andBump-Mapping
Reflectance Field BTF Rendering
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
ResultsResultsResultsResults
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
Conclusions and Conclusions and Future WorkFuture Work
Conclusions and Conclusions and Future WorkFuture Work
in-depth analysis of measured BTF datain-depth analysis of measured BTF datanew approach to BTF renderingnew approach to BTF rendering
high-qualityhigh-quality real-timereal-time
moderate storage requirements for high-moderate storage requirements for high-frequency detail materialsfrequency detail materials
combine with Image Based Lightingcombine with Image Based Lighting
University of Bonn University of Bonn Computer Graphics Group Computer Graphics GroupJan Meseth, Gero Müller, Reinhard KleinJan Meseth, Gero Müller, Reinhard Klein
AcknowledgementsAcknowledgementsAcknowledgementsAcknowledgements
Funded by European Union under the Funded by European Union under the project RealReflect (IST-2001-34744)project RealReflect (IST-2001-34744)
www.realreflect.orgwww.realreflect.org