best way to get rid of noise with pmc?

[miohn]

Hi,

PMC gives me a nice lightning, but I get strong noises in walls and shadow areas.

Image is about 6000x7000 px and I have a small amount of blooming in camera setting.
But even with 2.000 samples (and therefore a very long rendertime) I cannot get
completely rid of some noisy areas.

What values should I tweek without getting to blured?

thanks
Mike

[miohn]

btw. with DL it renders with about 500 samples absolutely
noisefree und sharp/grisp.

Maybe I have a wrong setup for PMC?

regards
Mike

[brasco]

A lot of things can cause fireflies and noise, it's usually small, overbright light sources combined with refractions in my experience.
I'm not sure about how best to reduce it other than using larger less bright light sources.

cheers
brasc

[whersmy]

less glossy values and as low as possible poly emitters ?

[miohn]

well I have one sunlight/daylight and one arealight to
lighten darker areas/corners (which become much darker when using DL-Mode)

I encountered, that post processing (bloom power and glare power)
in cameratag are causing that noise.
But its an overall noise - no fireflies.

thanks
Mike

[momade]

i think that bloom and glare don't have any effect on noise and fireflies, as they are post effects.

use the 'hot pixel removal' setting in the 'camera imager tab' of your 'octane camera tag' with a value between 0.4 and 0.7 this will reduce most fireflies without any significant loss of sharpness / quality.

very often instead of 'PT'-engine using 'DL'-engine in 'GI_DIFFUSE' rather than 'GI_ABIENT_OCCLUSION' with a high values in 'specular depth' (i.e. 16); 'glossy depth' (i.e. 16) and 'diffuse depth' (i.e. max of 8)results in great, noise free images. especially refractive materials cause tons of noise in 'PT'.

a workaround i used for this MUST-'PT'-scene [https://vimeo.com/93034165] was rendering in 'PT' at only 180 spp but double resolution (yes 4k resolution) and 'filter size' set to 2 plus 'hot pixel removal' set to 0.4. then in post i denoised the oversized render a bit and shrank it to the final resolution, to get rid of the heavy noise in the output. the result was far better than rendering at 1000spp and saved me 40% of rendertime!

[miohn]

thanks!

will try that DL mode with higher settings!

For Animation I mostly also render at 150 - 300 samples and use
a bit noise reduction. But this doesn't work for that still in my case.

regards
MIke

[momade]

remember to use LD in DIFFUSE mode, not in AMBIENT_OCCLUSION mode!

[acc24ex]

good results you got there momade, this is "oldschool" trick which we need to be reminded more - also I think for refractions, increase the refractive blur - just to make sure you don't get those a lot

what did you use for the water noise?

also for vimeo to embed use

Code: Select all

[vimeoid]93034165[/vimeoid]

[momade]

right i missed out on that. refractive blur was et to 0.32 to reduce fireflies caused by that.
water is done with hoz4d. and thanks for the vimeo-embed-tip.