HDR vs Physical SKY

[masterzone]

Hello Guys...Corona user since Corona 4...
I'm approaching to get some archiviz animations request from some clients, exteriors and interiors scene.
Often I'm using the Physical Sky for exteriors and some HDRIs for interiors render.

About Interior renders, what do you think is it the best way between HDR or Physical sky to avoid noise and long render times?
You know Corona Render is settings free and I would like to find some tricks to speedup render process.
Usually I don't touch anything from advanced settings so render times is not a problem right now, but during animations putting Flicker free GI get some times to render a single frames...setting the noise level is a good way but I don't know if there are some settings to put down...

Any tips?
Thanks

[Nejc Kilar]

In my experience and broadly speaking the procedural sun & sky set up will be faster to render out than an HDRI. That said I personally do like to use HDRIs for certain interiors because they can get you really nice subtle details in the lighting - for example you get some greens from the ground, some nice orange from the brick building thats in the HDRI etc etc.

That said the procedural setup is awesome because you have total control over the actual light sources - sure you might need to model some of the environment to get those HDRI like subtleties (that are typically hard to notice anyway) but it tends to render faster. And again, you really can set up the lighting any way you please.

As far as cutting down on render times, you can try the usual GI vs AA balance tweaking but that in my experience gets you minuscule improvements. Corona is optimized as is. You do want to switch the UHD cache to the animation preset though and if you don't mind sacrificing realism then lowering the MSI to 1 might help you clean the noise faster (but the lighting will be darker and some materials less "intense").

Other than that personally I just let it render :)

[masterzone]

Thank you so much for your explanation...very useful and very closed to my thought...
Thanks
Alex