First look at Corona

[lacilaci]

Hi, my first post here... And my first run with corona and interior renderings.. Lit with only HDRi environment. PT+HDcache

[eugeniostephan]

How you can use fur???

[lacilaci]

Magic ;) ...it's corona scatter (1 strand 160 000 times over 2 carpets)

[Ludvik Koutny]

You can raise white multiplier value to get rid of that white burn. You will find it in post processing rollout ;)

[lacilaci]

You can raise white multiplier value to get rid of that white burn. You will find it in post processing rollout ;)

You mean highlight burn? I see no white multiplier, only intensity multiplier..

[Ludvik Koutny]

Right, sorry, i use old naming...  yes, highlight burn ;)

[lacilaci]

Actually, the raw .exr output wasn't having any overbright areas :D I did this in post, I kinda wanted to have some little overexposed areas. Is it so bad? I'm gonna take a look at different monitors...

[Ludvik Koutny]

Actually, the raw .exr output wasn't having any overbright areas :D I did this in post, I kinda wanted to have some little overexposed areas. Is it so bad? I'm gonna take a look at different monitors...

It's not bad... I mean, in theory it should be possible to take a photo when there is nuclear bomb exploding on the horizon seen out of the window. So let's assume you wanted to achieve that :)

[maru]

Or you could just save your image to .hdr and do magic in photoshop.

[lacilaci]

Well I just said I'm using .exr output (full float 32Bit)

[Chakib]

Fantastic result ! but i agree for the burning areas, the post processing can hadle that easely or hdri like said above.

[lacilaci]

nevermind... I will add other views without overbright areas, once rendered but I have a problem. I can't seem to find a good balance in quality/time with the PT sampling value. This first one was 128PT samples and it took about 2hrs to render in 1080p (the picture here was downscaled to 720p). I think it's not that bad for an old q6600, however I believe it can do better. I raised the PT to 256 but after 20 min or so I could not see any change in a refresh when updating. So does it make any sense to go higher than suggested max of 64 or should I even use lower values for a situation like this?(tried default 16 but it was very noisy even after an hour)... I'm rendering now with 32 it does look good after 20min. I'll see what I get in an hour. And yeah, another question how big impact does changing the update interval value have? I now it's good to raise it when rendering above 2k res. but does it give any significant speed gain or it's not a big deal to have it at def. 1000ms?

[Ludvik Koutny]

PT samples is not a quality value. And it's defaulted at 16 for a reason. It's a value that defines balance between GI sampling and AA sampling. Lower values will devote more sampling to AA (AA, DoF and Motion blur), while higher values will devote more sampling to GI. More GI sampling is useful only in scenarios more difficult for GI, like rooms with very small light entrances or lots of glass.

In your case, value of 128 is an overkill, even value of 32 is, and value of 16 (default) should work just fine. You might actually want to decrease it to something like 12, if you enable subtle DoF, or even to 4-8, if you make DoF effect very strong (some closeup with very blurred background for example).

If you want to squeeze some more optimization, then try to set samples multiplier in lights frame of render settings to something like 5-6 (default is 2), but even here, don't go to extremes (like 10).

About update interval...  i would not touch it unless you have a good reason to ;)

[lacilaci]

Oh, thanks. It makes much more sense now. The light samples multiplier in render settings does affect even the environment HDRI sampling and emission of materials or it's just for regular light objects? Thanks again for the explanation.

[Ondra]

Its for all light sources (hdr, geometry, coronalights). Corona does not differentiate between those