Image Space Gathering Austin Robison Predictive Rendering - - PowerPoint PPT Presentation

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Image Space Gathering Austin Robison Predictive Rendering - - PowerPoint PPT Presentation

Image Space Gathering Austin Robison Predictive Rendering Phenomenological Rendering Robustness Robustness Speed Speed Controllable Accuracy Appearance Example Phenomena Soft Shadows Depth of Field Motion Blur Color Bleeding


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Image Space Gathering

Austin Robison

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Phenomenological Rendering

Robustness Speed Controllable Appearance

Predictive Rendering

Robustness Speed Accuracy

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Example Phenomena

Soft Shadows Depth of Field Motion Blur Color Bleeding Subsurface Scattering Glossy Reflection

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Plan of Attack

Identify salient features of phenomenon Find cheap approximation for some or all of those features As hardware and techniques improve, find better approximations that capture more features

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Glossy Reflection

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Selected Previous Work

Percentage Closer Soft Shadows (PCSS) [Fernando 2005] Reflection Occlusion [Landis 2002]

See Paper for Additional Work

Courtesy of Industrial Light & Magic

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Variable Radius Blur - Spreading

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Variable Radius Blur - Gathering

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Cross Bilateral Filtering

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Image Space Gathering

Image space, post processing convolution with a two-pass signal dependent filter General framework for blurring

Tailor our parameters to implement the desired phenomenon

Filter integral can be computed many ways

We chose to point sample and MC integrate

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Algorithm Pipeline

Rasterize Requests Ray Trace Reflections Blur and Composite

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Position Reflection Normal trefl

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Phase 1: the parameter search

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Phase 2: the gather

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Undersampling Artifacts

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ISG

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PCF (Screen Space)

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Future Work

Add structure to filter kernel sample distribution

Approximate anisotropic BRDFs, shaped area lights, lens bokeh, etc.

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Acknowledgements

NVIDIA Research Randy Fernando and Louis Bavoil

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Questions?

arobison@nvidia.com http://www.nvidia.com