Force iray to have more iterations
Leonides02
Posts: 1,379
Hello All - Is there any way to force iray to calculate more iterations? I have it set to 99.9% convergence and the max "passes," but I'm still getting noise in my render and it only takes around an hour to converge. Can I force it to bake longer?
Thanks!
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Under Progressive Renderign you could try upping the Rendering Quality setting. I'd suggest upping Max Samples too, but it sounds liee those may not be a problem.
Thanks. Max samples I have set to maxiumum at 15,000. I wonder why they won't let you go abve that limit. Seem arbitrary.
Click on the little cog at teh right end of the slider for Maz Samples, select 'Parameter Settings' and then uncjeck 'Use Limits' and then click Accept. You will then be able to use a higher value.
Define "noise." If it's a darker peppery look, that requires a deeper convergence threshold. If it's white speckles, those are fireflies, and are combated in a different way.
Simon's suggestion of Rendering Quality is how you force deeper convergence. Values under 1 will reduce the threshold requirements to assessing converged pixels, while values over 1 will increase the threshold. The higher the threshold, the more Iray must work to converge pixels. A 2X increase in quality about doubles rendering time, but doesn't always double "quality," as that's subjective and depends on the scene. Try a vale of 2, then double it until you find a good compromise.
No render should require more than 15,000 passes. That strongly suggests some issues with the scene, and they need to be fixed using other means.
Thanks, Simon. I'll try that.
Yes, it's a dark, pepper look. There are some fireflies, as well. Thanks for the suggestion on the Render Quality.
I think the 15,000 passes aren't actually happening. Iray is reaching the converging target first.
I'm also checking into using Innobright's Altus. I had great success with that with Octane.
Hello! I have almost the same question but...
How can I use make iRay render more than 15000 iterations? I have some scene with fog, lights and other stuff, so in total it ook about 20h to render and stoped at 15k iteratons.
But image still looks grainy and at the moment I see no way to make it better :(
If it's still grainy after that many iterations, the scene probably needs more light, not more iterations. How have you set up the scene lights? (The procedure is a little different for the different types of light.) You can either adjust the Tonemapping settings during rendering (in the Render Settings tab) or use postwork to bring the finished render brightness back down to what you want.
This may not apply, but I use Affinity Photo myself, and the denoiser is pretty good at keeping detail and removing any noise. Probably Photoshop, Lightroom, GIMP etc have a good denoiser as well.
On the render side also check if you havent have too much scattering surfaces, like mirrors, chrome reflections all over the place, in my experience those kind of renders do (sometimes) seem to have some influence on the noise level. It also helps if your light can escape somewhere.
There are limits to the use of iterations, as you can tell the first few iterations are extremely noisy and then it appears to go flat in it's progression really quick, it could go on forever exchanging noise for noise.
Some scenes just require extra tweaking. Consider your materials and lights first for problematic area's, second consider your render settings, third consider your filter options, fourth consider your image editor of choice.
To render the amount of cycles YOU like, simply turn off "Render Quality Enable".
If you want more than 15000, click the little gear icon at the "max Samples" slider and uncheck "Use Limits".
Than you can set any value you want. For very high values make shure to incease the "Max Time" as well.
The render will stop either when the max samples or the max time value is reached, depending on what happens first.
The "Render Quality" lets Iray choose, when a scene is OK depending on the percentage you set. This can vary a lot, depending on the scene.
If Iray stops it after 3000 cycles because it thinks it's OK or you set the max samples to 3000 with Quality "off", the result is the same.
If you render to a new window you can open the render settings at the left of this window during render. Just move the mouse to the border and you will see that you can open a frame there. You can change these values during render.
i.e., you have set it to 5000 max samples and during render at 4500 you see it still needs more, you don't need to start a new render.
Grain is usually more in darker scenes. Less light = more grain.
One way to get rid of it is to play around with the tone mappings, i.e. the exposure setting to make it a bit brighter and darken it later in your photo editor.
Jup, see next comment... Must be the other way around. Add light and decrease brightness with the tone mappings.
Kind regards, Eagle99
Changing tone mapping settings is not the same as adding more light. Tone mapping will give you the look you want, but is not a substitute for more lighting as far as the rendering engine works.
Thanks to you all! Seems I looked to the differend direction of solving my problem.
You're right, it's quite dark scene in general, so adding lights is no option.
Using Tonemapping sounds as a good idea.
Thanks!
Will let you know how it works ;)
What we're saying isn't "add lights", it's "turn up the lights already in the scene". You can then adjust the render brightness back down with the Tonemapping controls (or postwork). You need the extra light to improve the efficiency of the render (which should reduce graininess, among other things), then you need the Tonemapping adjustment to fix the scene exposure.
Note that the exposure settings in the Tonemapping sub-tab are optimised for a bright cloudy day outdoors. If your scene isn't like that, then you must learn how to juggle light levels and exposure settings, otherwise you will never get your scene to render with the "proper" level of brightness.
No, or not optimally. What's needed is pseudo "ambient" lgiht to shine into the areas that are currently relying solely on bounced light (which requires longer as the rays have to bounce just right to hit the source). This lightens the whole scene (and reduces contrast) which is where Tone Mapping (and/or post work) come in.