Hi, Sorry that I used the wrong list. But I hope you have nothing against continuing this discussion on this list.
I don't know every detail of the implementation. But i assume that you use something like spreading rays (fitted to the camera and film) for every pixel on a fixed grid, where the gauss function defines the fine spread of the rays from every pixel center. I understand that this is most likely faster as to start rays from anywhere or to let them have different angles. But if you have samples with errors, then this error will only contribute to one pixel. Especially caustics will take a long time to get clean if they are a seldom occurrence, because a neighbouring pixel might just miss nearly any time. If you would send in rays which "start at subpixels" of the film, then it is much more likely to get a better average (lower error), because most samples contribute to multiple pixels. A firefly found at the film-grid-intersection would evenly affect at least four pixels, giving that ray four times the probability to contribute the same result to all those pixels. Rays close to the center of a pixel will loose that effect. That way it would be about 2 times less noise in average. So i would assume that this sampling method would give better results (in same rendering time) as long you don't double the overall computation time for every sample. Especially more complex scenes (lot of bounces, comparably less important ray creation and weighting on the film) should benefit from it. Greetings from Tobias Oelgarte Am 27.10.2012 23:45, schrieb Brecht Van Lommel: > Hi, > > This is a topic to discuss on the bf-cycles mailing list. We use a > different pixel filtering method which fits better on the GPU. If you > set the filter width to 10 then yes, you might be wasting half the > samples. But for a typical filter width the number of wasted samples > would be quite small in my opinion. Still it would be good to improve > this, but I'm not sure where the half the samples number comes from. > > Brecht. > > On Sat, Oct 27, 2012 at 11:16 PM, Tobias Oelgarte > <[email protected]> wrote: >> Hello, >> >> I'm curios why i never see fireflies in cycles that affect more then one >> pixel. I have chosen to speak about fireflies, because they are the most >> unique sample that one could observe. It doesn't matter if set the >> gaussian filter to 1.5 or 10. The fireflies, no matter how strong they >> are, only cover one pixel. I see no distribution to other pixels of the >> film. If I'm not mistaken then i should see this sample contributing to >> at least four pixels (except the sample is perfectly centred and >> gaussian is 1.0). >> >> So I'm wondering why this samples do not contribute to neighbour pixels. >> If they would, then it would expect a significant noise reduction. >> (about half the samples for same result) >> >> Greetings from >> Tobias Oelgarte >> _______________________________________________ >> Bf-committers mailing list >> [email protected] >> http://lists.blender.org/mailman/listinfo/bf-committers > _______________________________________________ > Bf-committers mailing list > [email protected] > http://lists.blender.org/mailman/listinfo/bf-committers > _______________________________________________ Bf-committers mailing list [email protected] http://lists.blender.org/mailman/listinfo/bf-committers
