<p dir="ltr">I think bidirectional methods will at some point become the standard for production rendering. It's certainly something that would be great to have in Cycles.</p>
<p dir="ltr">There are various unsolved problems there still, handling outdoor scenes, image caches, how to apply certain tricks in this context, etc.</p>
<p dir="ltr">It might take a while still before this gets used for animation a lot, because you're not so much speeding up rendering, but rather making difficult light setups possible that would now be avoided.</p>
<p dir="ltr">Anyway, very interesting stuff to keep an eye on.</p>
<p dir="ltr">Brecht.</p>
<p dir="ltr">On May 10, 2014 8:30 PM, "Marco G" <<a href="mailto:digitalbath86@hotmail.com">digitalbath86@hotmail.com</a>> wrote:<br>
><br>
> Ah well i thought this one was a lot better than other similar or offline methods.<br>
> Regarding such approximations (irradiance caching) i tried to involve a couple of guys in the past months but without success yet.<br>
><br>
> Approximations aside, the upcoming Siggraph seems will have a nice focus on<br>
> more advanced light transport, focusing on usability from the VFX and Architecture side too, <br>
> and indeed such approximation seems are going to disappear in some way,<br>
> or at least progressively abandoned...according to these slides path tracing is the most used<br>
> but it seems industry proven renderers are considering/investigating more recent and advanced methods too. (see next link) **<br>
> In part it's a matter of "breaking" artists workflows again, and the good visual feedback unidirectional PT provides.<br>
><br>
> Perhaps simple path tracing will be replaced by some BiDir derivate, how you see this trend?<br>
> There will be a course held by Pixar, Fajardo, the Corona render guy, Nvidia, Next Limit...<br>
> ** <a href="http://www.iliyan.com/publications/Siggraph2014Course">http://www.iliyan.com/publications/Siggraph2014Course</a><br>
> ** Syllabus<br>
><br>
> One of the guy behind Vertex Connection and Merging is currently working at Solid Angle,<br>
> and VCM is going to hit Renderman 19 too (and already integrated in Vray and Corona, see link, last sildes)<br>
> <a href="http://cgg.mff.cuni.cz/~jaroslav/papers/2014-ltstutorial/04%20-%20ltstutorial%20-%20ppm+bpt%20-%20georgiev%20-%20notes.pdf">http://cgg.mff.cuni.cz/~jaroslav/papers/2014-ltstutorial/04%20-%20ltstutorial%20-%20ppm+bpt%20-%20georgiev%20-%20notes.pdf</a><br>
><br>
> By the way, a first implementation of VCM on GPU has appeared, <br>
> and this link in particular also focus on making difficult light transport algorithms more efficient on GPUs.<br>
> <a href="http://cgg.mff.cuni.cz/~jaroslav/papers/2014-gpult/index.htm">http://cgg.mff.cuni.cz/~jaroslav/papers/2014-gpult/index.htm</a><br>
><br>
> Lastly, found this one which improve BiDir dramatically according to the examples, but still unreleased.<br>
> <a href="http://cgg.mff.cuni.cz/~jaroslav/papers/2014-onlineis/index.htm">http://cgg.mff.cuni.cz/~jaroslav/papers/2014-onlineis/index.htm</a><br>
><br>
> So to conclude, BiDir or some of its evolution will be the next state-of-the-art approach?<br>
> How feasible will be for Cycles to switch to BiDir in the future, if it will be proven to be the best choice? (given enough man-power)<br>
><br>
> Regards, <br>
> MG<br>
><br>
> > From: <a href="mailto:brechtvanlommel@pandora.be">brechtvanlommel@pandora.be</a><br>
> > Date: Wed, 7 May 2014 00:03:28 +0200<br>
> > To: <a href="mailto:bf-cycles@blender.org">bf-cycles@blender.org</a><br>
> > Subject: Re: [Bf-cycles] Interactive GI filtering paper<br>
> > <br>
> > There's a lot of such filtering papers and it's closely related to<br>
> > irradiance caching. Certainly such methods would be useful for faster<br>
> > previews and rendering still images. There's simple algorithms and<br>
> > complex ones with different tradeoffs and inaccuracies. If people want<br>
> > to contribute code for this kind of thing that can fit fine.<br>
> > <br>
> > For animations however any method that does such filtering is tricky<br>
> > to get working without flickering / low frequency noise. The new<br>
> > papers in this area do not actually improve accuracy / reliability<br>
> > over irradiance caching as far as I can tell, they're worse but more<br>
> > general or quicker. Irradiance caching with all the tricks that have<br>
> > been developed for it over the years might still be the least flickery<br>
> > of all for the problem of diffuse indirect light.<br>
> > <br>
> > I don't know of other reliable algorithms for animation that also<br>
> > provide a big speedup for the simple cases. Mostly it seems that<br>
> > Cycles could handle the difficult geometry, shader lighting cases<br>
> > better with various changes, but if you want a big speedup for the<br>
> > simpler cases then some sort of filtering or caching method with the<br>
> > associated tradeoffs is the only solution I know of.<br>
> > <br>
> > Brecht.<br>
> > <br>
> > <br>
> > <br>
> > <br>
> > On Tue, May 6, 2014 at 10:35 PM, Marco G <<a href="mailto:digitalbath86@hotmail.com">digitalbath86@hotmail.com</a>> wrote:<br>
> > > Hi all,<br>
> > > just stumbled upon this paper, i'd be curious to know what Cycles devs think<br>
> > > about such technique,<br>
> > > results seems quite accurate and unlike other filtering/reconstruction<br>
> > > methods, it is done online interactively.<br>
> > ><br>
> > > link - <a href="http://graphics.berkeley.edu/papers/Udaymehta-IPB-2013-07/index.html">http://graphics.berkeley.edu/papers/Udaymehta-IPB-2013-07/index.html</a><br>
> > ><br>
> > > Would something like this be unusable, introducing a lot of inaccuracy? (or<br>
> > > complexity to the code..?)<br>
> > > Speaking more in general, isn't there any idea (for the future) to<br>
> > > help/simplify diffuse-indirect calculation? (not Irradiance cache related,<br>
> > > but something animation-friendly)<br>
> > ><br>
> > > Thanks,<br>
> > > regards.<br>
> > ><br>
> > > _______________________________________________<br>
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> > > <a href="http://lists.blender.org/mailman/listinfo/bf-cycles">http://lists.blender.org/mailman/listinfo/bf-cycles</a><br>
> > ><br>
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><br>
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