Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] Daily Builds => Topic started by: GeorgeK on 2021-06-24, 12:17:47
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It's time for a new playground, this time regarding the new Improved Sky - Altitude & Haze (Aerial Perspective). Please feel free to test this out and post your creations, If you have any questions, requests or critique regarding this feature please share them with us. The latest stable version of it can be found here: https://www.dropbox.com/s/aul162xh65q0vjx/corona-7-3dsmax-RC3.exe?dl=1
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=33613.0;attach=149964;image)
Basic details
Upon adding a Corona Sun & Sky, navigate to your slate material editor and paste or move your corona sky there. Within the Corona Sky Texmap, there is a section called Improved Model.
It is now possible to set your observer altitude in meters, higher values of this parameter will make the sky clearer and the horizon line less sharp. Next to altitude, you will find the Volume effect(haze), if true it enables a volumetric effect based on atmospheric settings from the current skymap. As expected, higher values of the Volume effect make the haze more dramatic/dense.
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=33613.0;attach=149966;image)
Happy Rendering!
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Can you explain what you mean by 'Observer Altitude', I would imagine the Observer is the camera height? But is this a real world altitude based on a physical sun/sky daylight system location, or is it altitude from 0,0,0 in the viewport etc etc
Or is it arbitary?
Or is it the altitude of the sun?
If it's the suns Z Position from 0, could this value not be obtained automatically?
I might just be getting confused because of the units being in metres - isn't altitude normally in 'degrees' above the horizon?
Edit: Okay so I just googled 'Observer Altitude' and got the following which would suggest it's the angle/height of the sun?
"Definition of "altitude" The angle of a celestial object measured upwards from the observer's horizon. Thus, an object on the horizon has an altitude of 0° and one directly overhead has an altitude of 90°. Negative values for the altitude mean that the object is below the horizon."
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Altitude as in your altitude when you're in a plane, or on top of a mountain, or standing on a beach.
It's set here independent of the camera height because no-one actually wants to create their scene 3,500 meters above the 3D host software ground plane - they want to create it on the ground plane, but then tell the sky "actually this whole scene is on top of a smallish mountain at 3,500 meters".
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Sure, think it was the word 'observer' that threw me :)
I've just set it to the Z value of my Corona Sun, seems to work ok.
Edit: Actually no it doesn't. It looks much better with a realistic altitude of the real world location of my scene.
So the altitude is affecting the Volume effect/haze quite a lot. The tooltip for alttitude states 'higher values give a clearer sky and less sharp horizon' But the higher I increase that value, the more colours shift in the haze/textures towards unnatural and it feels that the volume effect gets slightly stronger. I'd have expected with a clearer sky, the effect of volume effect/haze would be less pronounced.
It's probably just my understanding of what the settings are doing and affecting and how i'm interpreting the tooltips and adding them together.
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Using RC3 and the green tint is gone. However it tints now the scene in purple.. especially visible in refractions. Even if you activate the effect, then turn down to 0 the scene is still affected/tinted in purple slightly.
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Using RC3 and the green tint is gone. However it tints now the scene in purple.. especially visible in refractions. Even if you activate the effect, then turn down to 0 the scene is still affected/tinted in purple slightly.
Thanks Duron, we are aware of the issue and it's being investigated further.
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Sure, think it was the word 'observer' that threw me :)
I've just set it to the Z value of my Corona Sun, seems to work ok.
Edit: Actually no it doesn't. It looks much better with a realistic altitude of the real world location of my scene.
So the altitude is affecting the Volume effect/haze quite a lot. The tooltip for alttitude states 'higher values give a clearer sky and less sharp horizon' But the higher I increase that value, the more colours shift in the haze/textures towards unnatural and it feels that the volume effect gets slightly stronger. I'd have expected with a clearer sky, the effect of volume effect/haze would be less pronounced.
It's probably just my understanding of what the settings are doing and affecting and how i'm interpreting the tooltips and adding them together.
The sun doesn't have to be aligned with observer altitude in any way by the user.
Earth's atmosphere changes over altitude. The higher you get, the darker the blue sky due to a thinner atmosphere and less scattering, the thinner the ground fog etc - this is what this parameter simulates as explained by TomG.
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Maybe it would be less confusing if "observer altitude" should be replaced with "scene elevation"?
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I haven't installed the new version yet, but here goes my question:
Is the sun intensity reduced automatically when the sun gets closer to the horizon? I hope it does, because with the 6.1 that doesn't happen and I manually need to lower the intensity with guess work based on the position of the sun.
EDIT: I know this might sound like a kid wanting more and more, but it would be great if that behavior happened with the sun
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Maybe it would be less confusing if "observer altitude" should be replaced with "scene elevation"?
+1
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I haven't installed the new version yet, but here goes my question:
Is the sun intensity reduced automatically when the sun gets closer to the horizon? I hope it does, because with the 6.1 that doesn't happen and I manually need to lower the intensity with guess work based on the position of the sun.
EDIT: I know this might sound like a kid wanting more and more, but it would be great if that behavior happened with the sun
Not sure what you mean, because sun intensity is getting reduced when it gets closer to the horizon. It always did, since very beginning.
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Just to add that the actual Intensity parameter doesn't change, but the light color and intensity from the sun in the scene (at that Intensity setting) does indeed change, as in all the demo videos, tutorials, etc. You could share an example scene and result if you are not getting that effect.
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Sorry. You're both right.
I guess I usually feel that artistically looks better with an even dimmer sunlight and larger size, increasing the penumbra faster. But that's my personal artistic choice I guess.
Thanks.
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So what I was talking about is this.
See the photo attached please.
The skylight is still strong when the sun is low, but the sunlight is much dimmer. With corona sun and sky what I feel it happens is that both the sun and sky lights get dimmer together at the same rate
Probably the photo attached was an HDR, but still it looks closer to what the human eye would see.
I'm not expecting Aerial Perspective to give this result automatically, so you can disregard my "request". I just wanted to clarify and explain why I always feel I need to change either the intensity of the sun or the sky.
Also frequently I use two skies: One for lighting and reflections and one for background. This is for the same thing. When the sun is low, the reflections of the sky and the skylight in general feel too low in comparison with the sun.
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No it really does work correctly, I was surprised myself how well. The previous model didn't (as good at all).
Of course, both get dimmer but not at same ratio which you can compare when you compensate exposure (and normalize it).
When comparing to photos or things you remember visually, you have to account for all the variables that happen. Dynamic range (of your eyes or camera), post-production, clouds in the sky, architecture & nature occluding and bouncing light, etc.
Right now, minus the existence of cloud simulation within the Sky model itself, it replicates the light almost exactly to reality.
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No it really does work correctly, I was surprised myself how well. The previous model didn't (as good at all).
Of course, both get dimmer but not at same ratio which you can compare when you compensate exposure (and normalize it).
When comparing to photos or things you remember visually, you have to account for all the variables that happen. Dynamic range (of your eyes or camera), post-production, clouds in the sky, architecture & nature occluding and bouncing light, etc.
Right now, minus the existence of cloud simulation within the Sky model itself, it replicates the light almost exactly to reality.
Good to know your opinion. Thanks.
I'm taking artistic license in that respect then.
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Absolutely, so am I :- ). And photographers :- ). Like.. how popular did Sky Replacement "A.I" got in last year? There is Luminar,etc. so many apps. Even before that, EV filters, Polariser filters, Lens coating, etc.. it all contribute so vastly to how we perceive skies in photography.
In terms of light (&shadows) cast, until Sky models have Cloud simulation, you have to change all aspects (size, color, intensity) in artistic way to account for how sun would get diffused behind clouds. Or use HDRi.
I feel like in few years we'll get to that point at as well. Tools like Terragen were always trying to integrate the Sky models in such way.
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I think you should rename Volume Effect to Snoop Dogg Effect, just kidding.
I'm not sure how to use this VE with interior scenes.
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It's not an interior effect tbh - for that, the full volumetric material (Global, or on an object) would be the correct solution. This one is definitely intended as the haze and aerial perspective seen across long distances while outdoors.
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It's not an interior effect tbh - for that, the full volumetric material (Global, or on an object) would be the correct solution. This one is definitely intended as the haze and aerial perspective seen across long distances while outdoors.
Yeah, got it, thank you.
But I had hoped this feature will work with all scene (it's so quick and lean result)
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Testing the RC4 to check if the Magenta tint is gone. After a quick test in a simple scene, the same I used to test RC3, the issue seems to have improved a lot, but it isn´t fully gone. Maybe this is too subjective. Let me show an example:
RC3 vs RC4 comparison at Turbnidity 4: the improvement is massive.
RC3 vs RC4 at Turbidity 6 (or anything above 4.5), and the improvement is noticeable but still looking a bit weird to me. You can check the refraction pass to see how those glass surfaces are tinted when they shouldn´t, right?
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Can you just increase strength of the effect at low turbidity and get same result (minus magenta tint)?
I mean, get denser "fog".
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Can you just increase strength of the effect at low turbidity and get same result (minus magenta tint)?
I mean, get denser "fog".
After a few minutes testing the Fog with RC4, I noticed that, at Turbidity=2, increasing the Volume Effect multiplier not only makes the Fof effect denser, but produces unexpected results, like bands within the Zdepth range that are more dense and more heavily tinted and other areas that are less dense. I´m not sure what is happening, but doesn´t look like a natural effect to my eyes. I will post examples as soon as possible.
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Here you can check a simple comparison, same Turbidity (=2) for all, same altitute (=0) and just changing the multiplier of Volume effect multiplier.
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JulioCayetano, please use this topic for discussions about new haze. I moved related messages from daily builds topic here.
P.S. i also find that haze in RC4 is still a bit too pink in certain situations, but it's miles better than it was before.
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Here you can check a simple comparison, same Turbidity (=2) for all, same altitute (=0) and just changing the multiplier of Volume effect multiplier.
It looks kind of right to me, but I don't know what should be the ground truth as reference to judge by :- ).
But at least it doesn't have pinkish tint.
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Test with new Aerial Pespective. No Postproduction, direct render VFB.
Nice and fast effects with this new implementation.
Thanks
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Hi. I'm testing the new Sky, and having a problem. When using the new volume effect together with VDB-skies, I'm getting a purple box around the skies.
Is this a known issue, and are there any workarounds?
Uploaded two images showing the problem.
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Yes, known issue afaik - the new Vol Effect replaces any other sort of volumes for now, and adding volumes into the scene (eg OpenVDB, or perhaps even Vol Mat) won't render correctly.
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Thanks. Not great news, but at least I now know what not to do :)
Best regards
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Wait, just want to make sure I understand:
1. If I have the new Corona Sky Volume Effect enabled in a scene, all other volumetric effects (materials) in the scene will not render correctly?
2. Is there a way to render a scene with an HDRI *and* have the Corona Sky Volume Effect in the scene?
3. Is there a way to adjust the color of the volume effect?
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1. If I have the new Corona Sky Volume Effect enabled in a scene, all other volumetric effects (materials) in the scene will not render correctly?
I saw some reports about that, but i myself successfully rendered a scene with aerial perspective and volumetric clouds. I think that even if there are some limitations, but aerial perspective and volumetrics are not mutually exclusive.
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Hmm, it appears that it is possible to light a scene with an HDRI + Corona Sky (Multiple maps (LightMix) -> enable Vol. Effect (Corona Sky) -> Setup LightMix -> Vol. Effect is parsed into 'Rest (unassigned)'.
The Vol. Effect color and intensity can be adjusted from the 'Rest (unassigned)' channel in the LightMix.
That is pretty fascinating - is this a known workflow? (I had no idea this was possible).
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For me, the volume effect broke again. Not sure if it's the new daily build or something else.
It's a clean scene with just sun and sky and besides the purple tint, there is no volume effect whatsoever.
Could you please share the scene? Screenshot? Material setup...?
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Hello there,
I did a try in it and loved. Looking forward to work on more realistic scene.