1. GI is slow
Global illumination is important but slow. So people use fast approximations, …
Effects of Global Illumination Approximations on Material Appearance
Křivánek, Ferwerda, Bala
Thursday
10: :15

2. VPLs are fast, but… VPLs: artifacts VPLs: material change GI reference
… such as Virtual Point Light, or VPL-methods, based on Instant Radiosity.
But the problem is that the VPL methods can produce image artifact or change material appearance.
GI reference

3. Visual Equivalence for VPLs?
VPLs
reference ?
VPLs
reference ?
VPLs
reference
We wanted to know when the VPL methods produce faithful renderings … that are visually equivalent to reference renderings.
Effects of Global Illumination Approximations on Material Appearance
Křivánek, Ferwerda, Bala
Thursday
10: :15

4. ? ? ? ? ? ? ? Perceptual study Experiment Different shapes,
Artifacts?
Different material? ? ? ? ? ? ?
Experiment
Different shapes,
materials, and
illumination
Material change
To answer that question, we ran psychophysical experiments where we determine thresholds for artifact visibility and material change in VPL rendering … for different shapes, materials and illumination.
Material change thr.
Visually
Equivalent
Artifacts
Artifact visibility thr.
Effects of Global Illumination Approximations on Material Appearance
Křivánek, Ferwerda, Bala
Thursday
10: :15

5. Perceptual Foundation for VPLs
Apps
Results 
Thursday, 29 July, 10: :15 Perceptual Rendering Methods (2nd Talk)
So come check out the results of our study and some applications on Thursday morning. Thank you.
Effects of Global Illumination Approximations on Material Appearance
Křivánek, Ferwerda, Bala
Thursday
10: :15