Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Jadefox on 2016-11-06, 15:25:44
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Hi Guys
I was browsing the gallery and came upon an old post by Spike Spigel ( think his name is Sergey ) https://forum.corona-renderer.com/index.php?topic=6021.0 (https://forum.corona-renderer.com/index.php?topic=6021.0)
I was just blown away by the realism. He states its nothing more that Corona sun and sky and I read in the comments that he uses a color correction on his corona sky. I tried my best to recreate this but always end in a dirty blue sky. I have also contacted him but I suppose he is not so active on the forums anymore. Can anybody please assist me in explaining to me how I can recreate this rich blue sky
I would appreciate so much !!
Regards
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I think he only used Sun+Sky for lighting, so the background may be something else.
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Hi Maru
Thanks ,I see what you mean
I've put an HDRI in environment override and I think it closely resembles his background
Thanks for the advice
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I don't see any reason why it could not be CoronaSky on Spike Spigel's renders. It's just a blue gradient after all, exactly what what CoronaSky is.
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I've tried the color correction node Rawalanche
1. Increase saturation
2. Decrease gamma
3. Set the intensity of corona sky
( I am sure the above is not correct, it was just the only way I could try and simulate that type of blue )
But it always comes out, almost dirty and not that rich blue , I'm attaching screen shots to explain better
Regards
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I think that the green colours of the grasses and especially the trees and the dark facades of the house gives the sky that nice blueish vibe. If you make testrenders with a white scenery than it's just what it is.
My suggestion would be to add more vibrance to your scene and not worry that much about the sky intensity first.
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Is this what you are after?
(https://s11.postimg.org/mgiutt10z/SKY.jpg)
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You will never be able to get rich deep blue sky unless your enviroment is underexposed a little bit. Instead of trying to colour correct enviroment and potentially messing with scene lighting, i'd suggest you to use direct override or even replace sky in post processing stage.
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Actually, you don't even need to underexpose as long as your scene is dark to start with. Like the black house and darker foliage around it in the link above. You will often get that rich blue sky especially when sun is very high above horizon. I guess he just rendered nice linear images, and then did some postprocessing in PS to boost contrast. That's most likely what pushed CoronaSky into those more rich tones. Color correcting in right in the environment slot is a nonsense.
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Color correcting in right in the environment slot is a nonsense.
You're big on having the UI as tidy as possible. If correcting a background to be more appealing is nonsense then in what scenario do you see Direct visibility override as valuable? I'm genuinely interested because back in the day I remember comping skies to Vray renders where, IIRC, I used a black environment color in the render so the tree etc edge pixels would be correctly fixed and ready for comping, otherwise there would be artifacts. I've forgotten the right technical wording. Is this still something to consider in Corona?
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I dont think is nonsense, i think hes using the tool as intended.
Maybe its just me, but the sky system is a bit overexposed in corona when rendering with default values (just the sky color).
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Maybe its just me, but the sky system is a bit overexposed in corona
Agree, I feel the same.
Good Luck
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Maybe its just me, but the sky system is a bit overexposed in corona
Agree, I feel the same.
Good Luck
Isn't this just because the model assumes that sky is completely clear? It's like a supper sunny day with no clouds.
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Don´t know what the model assumes, but when I compare photos (clear sky, unmodded) with standard corona sky renders, it´s allways too bright compared to the rest and thus too washed out, even when the effect depends drastically from day/time.
But maybe the rest of my scenes is just too dark :) Cannot substantiate this any further, sorry. And since 1.5 I additionally have the feeling that the standard exposure for a cSun+cSky setup went from -3 to -3.5 for some reason.
I would setup many scenes by lighting with cSky + cSun but have HDRI in visibility override and reflection override. But as long as this exists (https://corona-renderer.com/bugs/view.php?id=2124) it´s just not possible to do this reasonable.
Good Luck
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Curious at which sun angles you get away with EV -3 -3.5? I have toolbar button that creates sun at ~55 angle, adds sky to enviroment and sets EV to -4. If i set EV to -3, then for clear unobstructed outdoor shots, my sun angle should go to 70-75 degrees, which is basically sunset-sunrise already.
And i didn't notice change in sky brigthness from 1.4 to 1.5. Might it be due to changes in materials (new PBR)?
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I can´t speak in angles because the first customer question after "when", "how much", and "do I get 300dpi" is usually "Is the sun lighting correct?". So our default maxstart scene comes with a daylight system and I never cared about it. But -3,5 covers a wide range, obviously you have a low highlight compression value. I use -3,3,3 (EV/HC/Contrast) to start.
Good Luck
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Well I agree with romullus. In a summer outdoor scene my EV will typically be around -4,2 with he and contrast both set to 1. And with these settings the sky doesn't look a bit overexposed.
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Had to test Corona 1.4 vs. 1.5.2 for another reason and did a simple check with a sun+sky system.
Render settings reset - then EX -3.5, HC3, C3. See the result. This is what I was refering to here:
https://forum.corona-renderer.com/index.php/topic,13785.msg89685.html#msg89685
Good Luck
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Is it sky or HC / Contrast that has changed? Did you try to do same comparison with HC1, C1?
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I´t the contrast setting which acts differently (forgot to check further before installing 1.5.2 on Max2014, reversed to 1.4 again now again). So it´s not noticable when using C1.
Good Luck
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Expected differences between 1.4 and 1.5:
https://coronarenderer.freshdesk.com/support/solutions/articles/12000019367-what-might-change-if-i-open-an-older-scene-in-corona-1-5-
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Well I agree with romullus. In a summer outdoor scene my EV will typically be around -4,2 with he and contrast both set to 1. And with these settings the sky doesn't look a bit overexposed.
Sorry to dig up a 2 and a half year old thread, but this is something I'm currently looking at at the minute. Now that PBR materials/textures are much more commonplace than they were back in 2016 when this thread was alive. I'm curious as to whether you're still finding -4.2 as a good EV value for exterior summer shots in bright sunlight?
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:) TBO these days I mostly use HDRI's. And when I use the Corona sun & sky, I often use it with a LUT, why the exposure value is set accordingly.
So I can't really say if values around -4,2 still is the sweet spot, but I haven't noticed any dramatically changes neither.
Hope it helps
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I just find, -4 way too dark too like Frood, hence why I asked. I seem to be -3.5, -3 at the minute too, was just curious that's all. The reason I mentioned PBR becoming more commonplace is that PBR effectively introduced the notion that the Albedo (Diffuse) is actually much darker than what we first perceived or should I say used.
So for example white painted stucco walls albedo being around 170,170,170 - on a sunny day, i'd expect a white stucco wall to look quite blown out, but if you set that up in Corona with a sun/sky both being on 1, at EV -4.2 it looks super dull and grey, yet changing it to -3.25, with a touch of HC (say 1.5), it starts to look as I'd expect it look in reality with areas of direct sunlight looking nice and white.
So I was just querying and curious as to whether the suggested -4ish EV originally stemmed from materials being too bright as opposed to incorrect sun exposure