photon glossy bounces

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Thursday, September 23, 2010
Houdini 11.0.513: Add support for glossy bounces to photon map generation and photon map lookups for PBR. The photon distance threshold can now be used to trade off performance and quality when using photon maps with glossy bounces. Larger threshold values will provide more accurate results while smaller values will produce faster (but less accurate) results. The sampling pdf is used to scale the threshold value, so sharper reflections will automatically require a denser photon spacing before the photon map is used (mirror reflections should never use the photon map). The default photon distance threshold of 1 provides a good starting point.
The potential for awesomeness is strong with this one. As of now, there seems to be a little problem with the type of reflection it picks up, as you can see from the two examples below which were achieved by turning the GI light on and off - it looks like it's picking up an almost diffuse reflection in addition to the correct (and very nicely blurred) glossy reflection. It's most visible in the suddenly appearing horizon line on the torus.

The scene contains one area light, and both torus and ground share the same standard material with everything turned off except for glossy reflection.

The good news is that the grainy image (without_photons) took 1:47 minutes, and the smooth one (with_photons) took 40 seconds including photon map gen. I like a lot

cheers,
Abdel

Attachments:
glossy_pmap.hip (799.2 KB)
with_photons.jpg (54.1 KB)
without_photons.jpg (53.3 KB)

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This is great news!
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brianBurke
This is great news!
yes this is great news indeed!

jason
HOD fx and lighting @ blackginger
https://vimeo.com/jasonslabber [vimeo.com]
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