Become a Pro at Redshift - Global Illumination

[@hockwiig]

Such a great video ! Full of really good tips, i've learn a lot, thanks !

[@BoldBreak]

Great, glad it helped. 😁

[@tricky.pixels]

Thanks for this...some great tips & info!!! And from a fellow Irishman too!! 🙂

[@BoldBreak]

Glad it was helpful!!! Nice, always great to see fellow Irish people in the industry :)

[@the_3rdKind]

Ive seen so many videos on the net about cleaning noise but cant find anything on cleaning up GI splotches. Did I hear right that its the denoiser that contributes to that?

[@BoldBreak]

Sorry for the late reply, The majority of denoising I do, is in post FX. Using the denoiser in redshift adds a variable in the rendering process which can be tricky to manage. But when I've used the denoiser it's never caused splotches unless the values are aggressively tuned. In this instance it's more the denoiser that causes splotches not your GI. Brute force tends to be the best engine for a moving image. Irradiance is known to cause splotchy noise. In some cases the GI will be noisy if it's trying to Illuminate areas of your scene but it does not have enough trace depth or samples to do so.

[@Pathfinder_tua]

how do i get the same global illumination settings as the standard renderer?

[@BoldBreak]

The GI settings in Redshift differ from standard. It is not possible to access the same settings as in standard.

[@andrearusky]

Why not using the latest version of Redshift with ACES? BTW something that I always wondering about the RS render settings is the "Unified Sampling Treshold". I understand it's very importand and it controls how sensitive the noise detection algotithm will be, but it's a bit diffucult to find out what value to put there. Will you be sharing some insight on this matter in your part? Also it's worth trying the "Automatic Sampling" in conjuction with the Threshold slider. Cheers!

[@BoldBreak]

Hey, Great point!! Aces colour will be in future videos. I've not got round to using Aces with RS yet in our tutorials. This video was heavily focused on understanding GI and the sub-samples. Colour profiles are overlooked and its a subject that deserves its own video. I agree that the unified sampling threshold is tricky to manage. It can really vary depending on your scene set up. But I'll look to explain this as we progress in the Redshift Series. Thank you for commenting, it helps shapes future videos.

[@iamopia]

I agree that this thing is tricky and I wrapped my head a lot about it. I guess the best explanation on this topic I've found is Saul Espinosa's video on Unified Sampling & Cleaning Noise, you can find it on youtube. he explained in details how Redshift works and thinks under the hood and with this knowledge I finally found out a process for tweaking samples for best speed and clear results. in short, we need to make sure that unified sampling algorithm works on clearing noise in the areas where it excels: motion blur, dof, anti aliasing and etc and not make it work on clearing noise in materials and lights. for this, we need to use local samples. I had to rewatch this video a few times to understand it fully, but it's one of the most impactful things I've learned about RS coming from Octane background.

[@BoldBreak]

​@@iamopia Yes it's tricky but once you learn how to master the samples and variable in each scene Redshift is lightening fast and very stable.

[@3D-VFX]

Oh man, this isn't the way to get clean renders, it's really simple the noise comes from the shadows, just control the shadows the get a clean render then in post you can bringing back the shadows.

[@BoldBreak]

This video is just looking at GI. Noise can appear across several areas of a render. Refraction and Reflection are also areas where noise can appear. There is a video in the redshift series which looks at how samples are calculated and gives a better understanding of how to optimize settings.