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Night rendering and strange white artifacts

Posted: Wed Nov 04, 2009 9:12 pm
by Michal Podgorczyk
Hello every one
I `m back to Maxwell after few years.


I`m trying to make night render, and I have problem with white dots.
Any suggestions?

Sl 14.83



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Building on the right is sang glass glas, suppose to look like this:
The okapane glass panels ale full models, like real world

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Re: Night rendering and strange white artifacts

Posted: Wed Nov 04, 2009 11:57 pm
by Bubbaloo
Looks like caustics to me. Are you using real glass in your windows? Maybe experiment with AGS (from the wizard).

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 12:14 am
by Michal Podgorczyk
thanks

its real glas with routhnes 30

i will experiment with ags in the morning

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 10:00 am
by JTB
Don't experiment.... Use AGS... :wink:

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 10:58 am
by zdeno
nie daj się wpuścić w maliny ;) zrezygnuj z przezroczystości w tych szklanych piaskowanych pustakach bo nigdy z tego nie wyleziesz.

za pomocą AGSu efekty będą opłakane i ni da sie uzyskać roughnessa.

to trzeba zrobić, albo poprzez mapę .mxi na emiterze, albo dając materiał ze zmultiplikowanym BSDF w ADDITIVE a światło ustawić PRZED ścianą i ukryć je przed kamerą.

W każdym razie nie brnij w przezroczystość bo utoniesz w render timach.

translator: don,t use AGS or glass. instead try to mimic this conditions wit opaque material , multilayered additie, or .mxi on emitter.

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 3:36 pm
by JTB
Interesting idea.... Have you ever tried that?

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 7:23 pm
by Michal Podgorczyk
Hi
I it seem that AGS is not a solution. The white dots are still here.
SL 12.00

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I want material which is transparent, semi transparent, like sandglass, like sketch paper, because I need the steel construction in side to be seen.


Here are some more sample photos, what I am trying to achieve.

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Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 7:34 pm
by Bubbaloo
How are your interior lights made?

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 7:41 pm
by Michal Podgorczyk
Interior light in the ground floor on the right are planes 50x200 cm
And in the upper are boxes with no top plane 5x5x5 cm

And in the building on the left there are boxes long tubes like, 5x5x400cm
And the roof above the entrance there are planes 40x40 cm

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 7:51 pm
by Bubbaloo
The white dots still look like unresolved caustic to me. Are you sure wizard AGS was used in that last rendering? Also, what kind of environment lighting are you using? What does it look like using only emitters? Only environment?

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 10:20 pm
by Mihai
Are you sure you changed all the glass panels to AGS? Because even in the upper right part of the render, that interior is much too noisy. Perhaps something to do with the emitter geometry/setup as well. Try rendering with multi light on and disabling each emitter slider to see if for one of them the dots disappear.

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 10:30 pm
by Michal Podgorczyk
Ok

This is no HDRI and no glass
just emiters insight the buildings.

SL 13.61

Image


more test tomorow

Re: Night rendering and strange white artifacts

Posted: Thu Nov 05, 2009 11:32 pm
by zdeno
There is something wrong with Your scene, I Think You should start from scratch, just live as few objects as possible and render region in the most noisy area , then add (unhide) some object and testrender region again.

I tried to compose opaque material but it was very borring to match this .mxi and testing emitters intensity.
With AGS there is no possibility to mimic roughness of glass (or only I am not familliar with this technique) because there will by no "substance" to "bend" light in different directions during passing light trough. Celofan ;) it is the best You can Get (celofan - this "plastic" wrap for flowers)

So I tried with real glass and that is results. Just 8.5 Sampling Level so noise will gone much more about 14Sl .
It is also crucial to render in the bigest resolution possible, and lower SL will look much more better than SL 25 with 800X600 picture (Bubballo invented)

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So You have to make this glass panels as simple as possible, in my case there are simple box
About this fireflies You have to watch other materials , mayby bump map of reflective layer is to contraste ? maybe some lost map in anisotropy is present ?
I sent you .mxs for tests

Re: Night rendering and strange white artifacts

Posted: Fri Nov 06, 2009 11:38 am
by Polyxo
Hi zdneno,
I also sometimes work with Glass Panels of that kind. Which Design would you suggest for the
area where these panels meet each other or its frame. Is it ok if they touch each other of would
a very tiny gap help cleaning up faster?

Re: Night rendering and strange white artifacts

Posted: Fri Nov 06, 2009 12:33 pm
by zdeno
In fact that was my first time with this light/material conditions, but it seems the best way is to live a tiny gap between all panels. It looks like in real world and all this Nd, attenutation stuff have chance to deal as in real life.