Surface Signals for Graphics

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Surface Signals for Graphics
John Snyder Researcher 3D Graphics
Group Microsoft Research
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Why Surface Signals?

• Many useful types of surface signals
• texture map Catmull74, BlinnNewell76 (color)
• bump map Max81 (normal)
• displacement map Cook 84 (geometric
  offset)
• geometry image (geometry)
• bidirectional texture function (precomputed
  shading)
• self-transfer texture (spherical harmonic
  coefs)
• Simplicity of regular 2D image
• Support on current graphics hardware (e.g. pixel
  shaders)
• Research questions
• How to generate and manipulate signals?
• What new graphics architectures?

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Surface Signal Research Projects
Creation precomputed radiance transfer
Parameterization signal-specialized param.
Rendering signal-based graphics architecture
Representation geometry images
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Motivation for Precomputed Transfer

• better light integration and light transport
• dynamic, area lights
• shadowing
• interreflections
• in real-time

point light
area light
area lighting, no shadows
area lighting, shadows
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Self-Transfer Signal (25D)
illuminate
result
Reduces shading to a 25D dot product
(low-frequency lighting)
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Self-Transfer Results (Diffuse)
No Shadows/Inter Shadows
ShadowsInter
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Self-Transfer Results (Glossy)
No Shadows/Inter Shadows
ShadowsInter
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Self-Transfer Demo
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Parameterization of Surface Signals
Geometry-based (know geometry only)
Signal-specialized (know geometrysignal)
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Measuring Parameterization Quality
2D texture domain
surface in 3D
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Geometric Stretch Metric
2D texture domain
surface in 3D
geometric stretch ?2 G2
Parameterize minimize surface integral of
geometric stretch
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Signal Stretch Metric
domain
surface
f
g
h g?f
signal
Parameterize minimize surface integral of
signal stretch

• geometric stretch ?f2 Gf2
• signal stretch ?h2 Gh2

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Conformal Floater97
Geometric stretch Sander01
Signal stretch Sander02
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(64x64 texture)
Results Scanned Color
Geometric stretch
Signal stretch
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Results Normal Map
Geometric stretch
Signal stretch
128x128 texture - multichart
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Results Precomputed Radiance Transfer
Geometric stretch
Signal stretch
25D signal 256x256 texture
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3D graphics 2D image processing?
not quite ? use images but of surface signals not
views

• synthesize images from 3D surface descriptions
• run-time flexibility change view, lighting,
  rendering params
• compactness single surface parameterization,
  not multiple views
• high quality (global illumination) resolution
  independence
• cheap creation no costly rigs operator, easy
  to edit
• as preprocess, convert 3D descriptions to 2D
  image reps (surface signals) to accelerate
  run-time
• signals can be represented as regular 2D images
• rendering via general, programmable image
  processing ops

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Rendering Factorization
global illumination computation is too expensive
from scratch
Preprocess(slow)
Run-Time(fast)
surface signals

• 3D surfaces (meshes)
• 3D graphics
• ray tracing, Monte Carlo integration, dynamics
  simulation, encoding

• 2D images, streams
• 2D image processing
• decoding, interpolation / decimation,
  programmable pixel shaders, sample gather

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End
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People
Microsoft Research 3D Graphics Group Jim Blinn,
Conal Elliot, Brian Guenter, Hugues Hoppe,
Charles Loop, Don Mitchell, Kirk Olynyk,
Peter-Pike Sloan, John Snyder, Turner Whitted
Collaborators Steven Gortler, Xianfeng Gu, Ziyad
Hakura, Jesse Hall, Jan Kautz, Leonard McMillan,
Pedro Sander, Zoe Wood