Questions about portals and HDRi size

[ficdogg]

I was wondering does the direction of the normals matter for portals?
Does the resolution of the HDRi play a role in direct illumination noise levels?

[maru]

Direction of normals does not matter for portals - we will be sure to add this info here: https://help.c4d.corona-renderer.com/support/solutions/articles/12000042132

As to HDRI resolution, it should not matter that much, but FAIK smaller resolution means slightly less noise.

[maru]

@Ben, the sunlight is from hdri?

[ficdogg]

Thanks, recently I was working on an interior render that was lit with only an HDRi and noticed that the indirectdirect illumination was quite noisy, so I'm just trying to troubleshoot it for future reference. Still, it rendered fairly fast at little over an hour to get it down to 5% noise level for 2304x1296

[Beanzvision]

Sorry, Scrap that last one, I left off the default shader. :\  1K vs 16K (16 passes - no denoising)

[ficdogg]

Sorry, Scrap that last one, I left off the default shader. :\  1K vs 16K (16 passes - no denoising)

Hmm, it does look like the high rez HDR produces slightly sharper sunlight. Out of curiosity can you post the indirect pass only as a reference?

[Beanzvision]

Yeah the sharpness is noticeable, even more so with a higher res render setting. Here are the indirect's

[Beanzvision]

Close up for fun :)

[ficdogg]

Interesting, I'll have to find some high rez HDRis and do some test renders to see how the render times change.

[Beanzvision]

The ones I use are from hdri haven ;)

[ficdogg]

The ones I use are from hdri haven ;)

Thanks that's a great site, didn't know about it.

[Eddoron]

Hi-res images obviously give a more detailed illumination. The question is: What do you need?
How large is the output? Do you want your HDRI to also serve as part of the scene? Do you need more diffuse shadows? etc.
There's a multitude of reasons for specific setups.
Also, don't forget that you can couple an HDRI with the sun object.