Author Topic: Corona Light material directionality noise even on preview swatches  (Read 751 times)

2022-10-05, 17:37:33

brr

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Dear corona team and forum users,

I am not sure if this question was asked before—I made a quick search and didn't find anything. If this question already exist somewhere, please delete this thread.


When I'm using coronaLight material (emit light active, corona default settings) and try to play with directionality, I get noise in my renderings even in simple situations when I'm using simple materials and not high directionality values for light geometry. The noise also persist on simple material preview swatches in material editor.

Please look at attached images:
01-directionality noise.jpg—comparison between material previews with different directionality settings. All samples have intensity 5, but even at 1 we can clearly see “splotchy” noise pattern
02-no directionality.jpg, 02-directionality.jpg—simple example how it looks with and without directionality.

Please, can someone clarify what's going on, and how can we avoid situations where we need to set the directionality for objects with coronaLight materials?

Best regards.

2022-10-05, 18:43:19
Reply #1

maru

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This is expected as lights with higher directionality are generally harder to sample (they are "smaller", they generate more focused, strong samples, etc). The noise is also visible in the material previews because those previews are rendered with just a few passes. You can increase the quality of those previews in the System Settings if you wish.

The question here is whether you really need lights with such high directionality. If yes, then you can try some ideas/workarounds:
- wait longer for the image to refine
- increase GIvsAA balance (maybe 32?)
- increase Light Samples Multiplier (maybe to 4?)
- use an IES instead of light with directionality
- use 3ds Max lights instead of Corona lights (they are less realistic but render faster)
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2022-10-06, 09:20:56
Reply #2

brr

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Hello Maru,

thank you for your fast and comprehensive answer.
I will try this solutions. For now, I made more fake position and size of the light stripe itself, so that i can lower the directionality and also intensity and get same visual result. That gave me faster rendertimes. 

Thank you again !