SkIndigo 1.1.16 and the fireflies

Pibuz · Post by **Pibuz** » Sun Apr 05, 2009 1:12 am

Sorry guys to report this again, but it's starting to get me a little angry..
With complex scenes (and, you know, architectural projects ARE complex scenes) I always have huge amount of fireflies, which make the render noisy and a little bothering. Obviously, longer render times won't lead to better results. Is it something which can be fixed or something? I really hope so, 'cos I really (professionally) cannot count on a renderer that makes such a bothering noise randomly in the final image.
I really don't understand why, cos I've already rendered other scenes of the same model, and they were (are) just fine, really good indeed. Whites are not too white, there is no glass unless necessary...

Tips? Suggestions? Any strategies to avoid this effect?
Thank you very much!

Oh, guys: don't get me wrong. I'm really grateful to you for all the work you've done. I'm only reporting this issue. Perhaps there's something we can do to make it better, that's all.

Post by **fused** » Sun Apr 05, 2009 1:48 am

which indigo version are you using?
is bidir enabled? it might help to turn it on. (there is a known issue with fireflies in the latest version of indigo)

CTZn · Post by **CTZn** » Sun Apr 05, 2009 2:57 am

A few hints Pibuz, I'm sure you know some already but why not remind them ?

- use a larger super sample value, in the range 3-5. Yes, that's big, but hopefully the wider the frame buffer, the more isolated nuked pixels will be. That should allow the render to overally reach a satisfying convergence while helping to nuke the bug

- make sure specular materials (specially transparent ones) are not intersecting with a medium-less ones (phong, diffuse etc), 0,2mm is about the minimal safe value between transparent geometries (down to 0,1 mm) and any others. Of course mediums can intersect other mediums as expected.

- In last resort give a shot to plain MLT ?

Pibuz · Post by **Pibuz** » Sun Apr 05, 2009 3:43 am

Hi guys thank for the support!

FUSED: I'm running Indigo 1.1.16, with skindigo 1.1.16. The render you see is calculated with BiDir PT.

CTZn: thanks for the hints mate. Now I'm trying to render with plain MLT to see the result. If the damn fireflies still show up I'll try modifying the super sample value: does a bigger number affect the "unbiasing" quality?
Specular mats don't intersect each other at all. In some cases I have TG geometry (window) colliding with a phong mat (metallic frame), but I hope this isn't the actual problem. I'd have serious problems detaching every window profile from its frame...

Post by **fused** » Sun Apr 05, 2009 5:20 am

try indigo 1.1.18. it should eliminate all specular related fireflies.

cheers!

PureSpider · Post by **PureSpider** » Sun Apr 05, 2009 6:01 am

Pibuz
Super Sampling just says how big the actual image is rendered and resized then...
So a Super Sampling value of 5 says Indigo renders your image 5 times as big as your output resolution and then scales it down by a factor of 5 for outputting it.

Pibuz · Post by **Pibuz** » Sun Apr 05, 2009 9:31 pm

Thank you Spider for your hint! Didn't know that!
Ok guys, this afternoon I'm going at my office and see what's going on with simple MLT. If still bad, I'll try some of your advices! Thank you so much!

suvakas · Post by **suvakas** » Sun Apr 05, 2009 9:59 pm

I always render with Bidir MLT if I want to get rid of the ff's.
Haven't tried with plain MLT though.

Pibuz · Post by **Pibuz** » Mon Apr 06, 2009 7:51 am

Thank you Suv! Another test I will do

Post by **fused** » Mon Apr 06, 2009 7:54 am

I think you should really start using indigo 1.1.18

benn · Post by **benn** » Mon Apr 06, 2009 12:05 pm

I'd be keen to know how you get on with 1.1.18 too..

kellpossible · Post by **kellpossible** » Mon Apr 06, 2009 3:49 pm

I posted a similar problem earlier, and switching to 1.1.18 fixed most of the problem, but I'll give super sampling a shot too. Just wondering, but could you achieve a similar effect to super sampling by scaling down the image after it has been rendered or is the process a lot more complicated than that.
(I'm sure that it would also depend on what image editor you used to do the scaling!)

CTZn · Post by **CTZn** » Tue Apr 07, 2009 12:03 am

Super sampling in Indigo is just a resizing of the frame buffer with a choosen filter, amongst the 3 available. So it can very well be applied in post by yourself kellpossible

About filters: the splat_filter should not be mn_cubic with default settings since it is putting the emphasis on nuked pixels. The splat_filter is the one used to apply pixels onto the native frame buffer, while the downsize_filter is the one that does the reduction job.

If the filters are not exposed in your exporter then you certainly want to set super_sample_factor to 1 and reduce in post.

Pibuz · Post by **Pibuz** » Tue Apr 07, 2009 2:37 am

Hi guys! Indigo 1.1.18 not tried yet.
I tried changing the supersample value to 3, but obviously I ran out of RAM.

CTZn:
1. what splat_filter do you suggest?
2. what downsize_filter values do you recommend?

Thank you again guys..

Post by **fused** » Tue Apr 07, 2009 2:57 am

Pibuz, i think you should try indigo 1.1.18 _first_ because it fixed firefly issues with specular meterials.

also you cannot nuke all fireflies with supersampling. sure, it might help a bit, but its definitely no good solution, especially not for the number of fireflies you encountered.

SkIndigo 1.1.16 and the fireflies

SkIndigo 1.1.16 and the fireflies

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