Grainy Iray renders
Ralf1958
Posts: 688
Probably I am coming up with a question that has been answered somewher but I can't find it.
So far I have done several renders with Iray, all very nice. The only Problem I have is with dark Scenes. No matter what Settings I choose, the Images turn out slightly grainy. I tryed increasing samples, time, converged Ratio and I played around with the noise filter. The results are still grainy. Is there a Setting I am missing?
Thanks! :-)
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Comments
Adjust tone mapping settings: A higher ISO, a lower f/stop and a lower shutter speed number should improve it.
You can also increase the cm^2 lumiance setting.
Ok! I'll try that! Thanks :-)
Personally I would keep the samples etc at default and first try the render quality setting, which is defaulted to 1.00, try 2.00 If it is still noisy increase samples and time out setting and switch on Noise filter.
PS Alternatively try adding some fill lights, say a plane mesh light, big soft shadows, small harder shadows. This will help with two thinks noise and reduce render times. This is also in combination of changing the Tone Mapping to let more light in to the camera. See real camera setting in Google.
Do I Need to Change Settings also in the noise degrain Filter after turning it on? I noticed it is on 0 by Default.
yeah I use a value of 1 but to be honest I haven't done much testing on what the optimal setting should be and the documentation is weak on this subject. But for me 1 seems to work ok.
Yes, indeed, the documentation is more then weak. It's hard to test every single slider, not knowing what to aspect. It gave me a headache trying to figure out how the blooming filter was working. I Thing I got it now :-)
Learning process... one step after another... :-)
I found that shader info helpful though, up to a point.
Not sure if it's my different light setup (meshes instead of points) or if it was due to ramping up the light map size, but my grain is gone and with it being stuck at X percent, not moving forward.
You might want to check the light map setting and ramp it up to 2048 or something like that. Doesn't hurt to give it a try. :)
I have done different Projects, some with normal lights (sphere) and others with meshlights, some have both. In this particular case it's mixed, but most of them are sphere lights. Maybe it's just me beeing to picky... as usual... see the Picture, some Little grainyness here and there... I just want to get rid of it... if ever possible :-)
Well, I am working on another Image right now. it's an interior Scene with HDR light coming through the Windows and interior Point lights and Mesh lights. Same Problem, the dark Areas are grainy. I tryed every trick you guys told me but nothing really helped. The last render is going for over 12 hours now, it's up to 12 %... still grainy. Am am thinking about cancelling it, supposently it wan't get any better waiting for other 12 hours. Any other ideas? Where are the Iray experts??? :-)
By the way, the Image I am Rendering is only 1600 x 900 px.
Ok lets strip this down to basics. First how are you setting up the surfaces, high glossy surfaces means high reflective more grain. What Tone Mapping settings are you using. What are your system spec btw?
Win 7 Home Premium
Daz 4.8 latest Version
Intel Core i7-4771 3.50 GHz
16 GB Ram
Nvidia Geforce GTX 750
Surfaces are all Iray materials. Not much glossiness especially in the dark Areas. No much reflectivity. I'll post a Picture for better understanding.
Here is the Picture. This was the first render. After this one i tryed all... higher ISO because this one was to dark anyways, but the result was grainy again, especially on Victoria. Then I tryed all the Settings suggested here, but always the same result. The last one, which is still going on since last night is on 12% now... but like I said before, GRAINY. And I don't want to add even more light...
OK by the looks it just needs more samples. So instead if increasing Render Quality increase Samples or Convergence. You got to remember that we are all learning Iray too and the people who really know this stuff will keep it to themselves, generally speaking.
:-) Yes, I know they Keep it for themseves! :-)
I already increased samples up to 15.000, should I go even higher than that?
And the convergence was at 100%.
For now I didn't go higher then the max values, should I try that? Hmmm...
To me that should be enough.
I just started up again. I turned the samples up to 150.000 Curious to see what happens... :-)
Haven't tried out dark renders yet, I'm really curious if you can get around that grain issue and how. I'd help you out, but I'm totally like "I have no idea what I'm doing" in terms of IRay right now. :|
It's probably also a camera settings thingy, but I have no clue about photography unfortunately. Every day something new to learn... :)
Haven't tried out dark renders yet, I'm really curious if you can get around that grain issue and how. I'd help you out, but I'm totally like "I have no idea what I'm doing" in terms of IRay right now. :|
It's probably also a camera settings thingy, but I have no clue about photography unfortunately. Every day something new to learn... :)
Good to see I'm not the only one with this Kind of question :-)
I am still learning, but this is what I would look at first.
I would not increase ISO, that (well in a real camera) will add noise.
How are the indoor lights set up?, they appear to be far too bright. Lights source near geometry can add noise. I enable the "Caustics" sampler which can help prevent that.
The window glass, how is that set up? Do not add a glass shader to the windows(it will add noise), you do not need refraction etc on window glass. Use a base material (such as uber base), add some glossy reflection and use the "Cutout"(for transparency) with a value of about 0.05.
Note: If the windows are solid (such as a scaled cube) make sure that "Thin wall" is disabled in the material, and drop any volume settings to stop refraction etc. If the windows are a single plane, ensure "Thin wall" is enabled.
Objects such as window glass do not need to have thickness. You use a material with "Thin wall". By default the shader will add the same surface material to both front and back faces and give it an infinitely thin volume.
There are light portals in Iray, but it does not look like we have access to them yet. You could add [plane] light emitters just inside(covering) each window, have the emitter set low and add a cutout value of about 0.02
I am still learning, but this is what I would look at first.
I would not increase ISO, that (well in a real camera) will add noise.
How are the indoor lights set up?, they appear to be far too bright. Lights source near geometry can add noise. I enable the "Caustics" sampler which can help prevent that.
The window glass, how is that set up? Do not add a glass shader to the windows(it will add noise), you do not need refraction etc on window glass. Use a base material (such as uber base), add some glossy reflection and use the "Cutout"(for transparency) with a value of about 0.05.
Note: If the windows are solid (such as a scaled cube) make sure that "Thin wall" is disabled in the material, and drop any volume settings to stop refraction etc. If the windows are a single plane, ensure "Thin wall" is enabled.
Objects such as window glass do not need to have thickness. You use a material with "Thin wall". By default the shader will add the same surface material to both front and back faces and give it an infinitely thin volume.
There are light portals in Iray, but it does not look like we have access to them yet. You could add [plane] light emitters just inside(covering) each window, have the emitter set low and add a cutout value of about 0.02
That's a good Point. I used the Iray thin glass shader for the Windows since they are single planes. The lights are from the "real lights" set. So I think they are setted right in Proportion of their surfaces. They probably look so bright because I turned the Bloom filter up to much (still experimenting with that one too). But I will try to Change the glass Settings, maybe it's the refraction Thing. :-)
Sorry, trying to follow this but your talking alien to me... you mention render settings of 1.00... where is that? I'm right in Render Settings and don't see that setting. Which column is it under? General, Render Mode, etc.... What samples do you refer to, under which column?
Trying to get a handle on this but folks just start talking too comfortably and newbies come in in the middle and, like myself are very lost in all this.
Gonna take allot of nudging to get my brain working in iRay mode since it's used to 3Delight for years and years..
thanks much
Render Quality is under Progressive Render but normally only used for Interiors I believe. Hey I new to Iray too. :P I used it as I was still getting some noise on surfaces that had SSS but boy does it hike up render times.
We are all new Szark but your renders speak for themselves. Your very very good at this and you understand allot more of the language. If we were speaking "hairdressing" I could talk circles around just about anyone technically but when it comes to this sort of stuff.. I'm like a new born, hideous child in the woods! lmao
So, now that my feeble mind knows where the Render Quality settings are, thank you so much now this one unanswered inquiry about "samples". I see those are also under the Progressive Render area but there are 3 bits with "samples" so which do I turn up to say that 150.00 value? My outdoor scene I'm still fiddling with looks very grainy and not in the least tight... looks sort of like a finished under painting to me! Except for the Moon, the moon looks OK (though I'd dearly love to figure out how to get it to "glow" a bit more)! lol Yea, I know, the entire set up is ridiculous looking! I'm well aware of that! Dusk's wardrobe I've been working on for him has taken a back seat to health issues I've recently had so I just threw on what is sort of done... part of a super-suit set I have for him....
So, now that my feeble mind knows where the Render Quality settings are, thank you so much now this one unanswered inquiry about "samples". I see those are also under the Progressive Render area but there are 3 bits with "samples" so which do I turn up to say that 150.00 value? My outdoor scene I'm still fiddling with looks very grainy and not in the least tight... looks sort of like a finished under painting to me! Except for the Moon, the moon looks OK (though I'd dearly love to figure out how to get it to "glow" a bit more)! lol Yea, I know, the entire set up is ridiculous looking! I'm well aware of that! Dusk's wardrobe I've been working on for him has taken a back seat to health issues I've recently had so I just threw on what is sort of done... part of a super-suit set I have for him....
Did you add any lights to this Scene?
Is that a plain background or is it an Environment map?
Did you add any lights to this Scene?
Is that a plain background or is it an Environment map?
Using the background option, the mapping for me, at least the image I'm using that I made, looks kinda stretched out when I put it in the iRay dome set up. So this way I have a nice tight look to the background that looks the way I expect it to look. There are two other lights in the scene besides the Moon (being the main source), I have one spots on the back to enhance the moon light effect but it didn't exactly work out and one point light in the face to light that up just slightly so he's not completely in shadow...
One Thing you Need to know is that lights have no effect on an Image set as Background (Environment/Tipe: Backdrop).
Are the lights you added, set on Photometric? (Lights Tab/Photometric mode/on)
If they are, then you Need to give them an intensity, turning up the Luminous Flux (Lumen) to something like 100.000 for a test.
Here you can set also the light temperature, on Default it's like daylight (6500). Going up it turns more blueish (colder) and going downwards it gets more reddish (warmer).
Last night while in bed I remembered my Blender Cycles learning and I watch a vid about Diffuse lighting. If some surfaces are really matt then you can get noise just the same if the surfaces are too glossy. Maybe that is your issue ralf.