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level 16 and still strong noise...

Posted: Mon Jul 11, 2005 10:01 am
by spekoun
Image

No post on image, of course. As you can see, strong noise at higer level... I used physical sky and sun. Have you any tip how to decrease noise? Except NeatImage, or sesizing from bigger resolution.

I know. Room is lit only by indirect light. It produces much noise. But at which level will it be clear. These types of scenes I do mostly. I bough Maxwel for his great light distribution. I do not any tricky light like in cinema. But that noise is killing me. I will render it on dual xeon during the week. Hopely it will be better.

P.S.:Of course i should wait till sampling level 100, but i will be old then... ;-)

Posted: Mon Jul 11, 2005 10:16 am
by Hervé
Frankly, I'd say it will not start to clear before 21... you are showing here the worst case for Maxwell right now...

don't worry ... we all are in the same boat.... :wink:

The problem is going to be real reflective surfaces first.. like your chrome feet for the leather coach... I doubt they'll ever clear at all... problem is that you can't clean these in NeatImage... because reflection image information is just not there...

Now if you want some real noise, put some half closed miniblinds to these windows... he he...

Unfortunatly there is no solution right now other than the poor solution you already mentioned...

BUT don't worry NL I am sure is orking very hard on these tiny dots... :wink:

Posted: Mon Jul 11, 2005 10:17 am
by Hervé
BTW, great model... looks promising.. :D

Posted: Mon Jul 11, 2005 10:32 am
by mverta
spekoun -

I have the strong suspicion your scene scale is off. Have you checked that? Something about the shadows and light looks like the scene is tiny...

_Mike

Posted: Mon Jul 11, 2005 1:09 pm
by spekoun
To Herve: thanks. I browse forum and read almost all topics. So I was afraid of but I expected this answer... ;-)

To mverta: Oh I hope I did not do this beginner mistake!!! I model it in cm and my scale in maxwell is 0.01. I think it is correct, isnt it?

Do you think using skydome instead of physical sky should help??? Then there will be no sun shine on the floor, of course...

Posted: Mon Jul 11, 2005 2:51 pm
by otacon
Im not sure if sky dome will help a whole lot, im doing a scene right now with sky dome and its still pretty noisy at level 16. It might lower it a little, but then it also wont look as realsitic.

Posted: Mon Jul 11, 2005 2:55 pm
by Mihai
Check this thread, might be of help in this situation:

http://www.maxwellrender.com/forum/viewtopic.php?t=4583

What is the material value for the walls?

Posted: Mon Jul 11, 2005 5:22 pm
by spekoun
Walls are diffuse. Diffuse has no reflectance. A read that thread, and checked all my plastics.... Evera are less then 50%

Thank for interest... ;-)

Posted: Mon Jul 11, 2005 5:29 pm
by Mihai
Yes but what diffuse value does the wall mat have? The white of the walls seems very white to me that's why I ask. If you check that thread you'll see the diffuse also matters, not just the reflectance. Diffuse is also reflected light.

Posted: Mon Jul 11, 2005 5:31 pm
by jomaga
Wrong!
Diffuse has reflectance. All materials in this world have reflectance
Reflectance is not the same as reflection. Reflectance is defined as the ratio of incident flux on a sample surface to reflected flux from the surface.
BTW, nice render.

Posted: Mon Jul 11, 2005 5:43 pm
by psanitra
Curenntly i`m working on new scene and i`m using skyligh + emitter except the psysical sun and and i have much less noise on level 11 then you on 16 :? and with SSS and Caustic ON with most of light coming through glass.
Send me a message on ICQ, you know the number....

Posted: Mon Jul 11, 2005 6:05 pm
by j_petrucci
spekoun, maybe your iage is still noisy because you made physical sunlight come through glass windows? light through dielectrics is still very noisy in Maxwel. :wink:

Posted: Mon Jul 11, 2005 8:30 pm
by spekoun
j_petruci: i read almosr all topics, so there is no glass in windows for sure.. ;-) this mistake i would not do...

jomaga: aha, i understand now. But i can set only diffuse in diffuse material. I did not know that this value affect reflectance. In plastic i can set reflectance and it means how much is that material reflective. So i was wrong about it. (and i was lasy find exact meanin in dictionary) ;-)

psanitra: I tried it too. But it seemed to me much slower. So I breaked render. I was impatient. I will conact you soon, thanks

Mihai: yes walls have 98%, I vanted my wall white. I will try it under 88% like in that thread is recomended. So if i understan good i should set for polar white wall RGB 224,224,224

Thanks to all for tips. I will correct it and let it render during night. Loojing for result. I will post of course... ;-)

Posted: Mon Jul 11, 2005 8:53 pm
by Mihai
Spekoun, to understand (although jomaga already explained the terms in his reply), think about how light interacts in the real world. You see an object, even if it is a wall, because the light is reflected from it and into your eyes.

So everything has reflectance, the term jomaga mentioned. What you mean by reflection is only the specular (sharp) reflections. So you have two types of "reflection", diffuse (rough) and specular.

If you have a diffuse mat, just don't set the diffuse color (how much reflectance (not reflection) it has) above 225-230.

If you have a plastic mat, then BOTH it's diffuse value and it's specular value should not exceed 225-230, because the plastic mat can reflect light back to you both as diffuse and specular.

Posted: Mon Jul 11, 2005 8:54 pm
by jomaga
No, sorry, spekoun, you did´nt understand the reflectance concept.
Reflectance is a percentege between the light reaching the surface and the light outgoing it. Basically, materials near black have low reflectance and materials near white have high reflectance, it does´nt matter if these materials have specular reflection or not, a white matte material have also high reflectance.
In other way, your windows have 98% white walls, with direct light. This probably causes a lot of light bounces with high reflectance --> more render time --> more noise.

Hope it helps!

(Sorry for my poor english)