Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: dj_buckley on 2023-06-26, 18:38:42
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Anyone know why I get this hard cutoff when trying to do an infinite ocean with Phoenix/Corona?
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Is there a distance limit on displacement perhaps?
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Hi @dj_buckley
could you please try to increase the horizon roughness option in the Rendering rollout of the Phoenix simulator?
Also, I would suggest checking this: https://docs.chaos.com/display/PHX4MAX/Liquid+Rendering#LiquidRendering-Ocean
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Horizon Roughness is set at 1 by default which is the highest it will go
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Also while I'm here, I took a look at the page you linked to. There's an example near the bottom for Ocean Subdivs. i just tried setting it to 8 as per the example for better distance rendering. This killed the scene completely and crashed. I have 128GB of RAM too.
Anyway I've attached the scene. It's very basic but takes forever to parse.
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To get rid of the bright "stripe" far away from the camera, go to your sky settings and set ground color to black. You can additionally toggle the "affected by sky" checkbox. I am not sure why it is working that way, but I guess it may have something to do with the reflectivity or refraction of the water material. You can additionally try different altitude, turbidity, fake horizon blur, and sky model settings to get various results.
Some additional hints:
- disable the displacement checkbox in the Phoenix object and plug the same displacement map into your water material - this way Corona will calculate displacement and it should be a bit faster
- you will need to set off-screen margin in the Phoenix object to about 10 - otherwise you will see the edges of the object close to the camera
- you can also go to the Preview rollout and disable the "show mesh" option - then the whole subdivided ocean mesh will not be visible in the viewport
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Thanks Maru - however, it seems like making the ground colour black is the only way to get rid of it completely. The downside to this is that it changes the sky colour completely. I do expect there to be some level of reflective gradient due to the angle, but it shouldn't be that harsh.
Disabling autobump makes it feel a little bit more natural, as does reducing the refraction below 1. Which I guess the ocean isn't 100% refractive right? Scum, dirt, silt, particles of whatever nature would stop it being perfectly refractive. But there will be times where perhaps you see the horizon and you want refraction at 1?
Also the closer to the horizon the sun gets, the more the harsh cutoff disappears.
It's just the harshness of the where the band starts that's odd. Absorption also affects it.
So i think it's definitely Refraction related and autobump was perhaps making it even more abrupt?
It would still be good to find out exactly what's causing it because I've not seen this happen with VRay in any tutorials i've watched but I could be wrong.
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Just adding to this as I discover more ....
Changing the displacement height makes the effect much worse.
I've attached 2 examples, the only thing that changes is the displacement height
So i'm still none the wiser as to whether its a refraction or a displacement issue. But considering it disappears completely with no displacement then I'm leaning towards yet another displacement issue.
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Hi, I randomly found out that it is probably related to environment distance.
Enable development and experimental stuff rollout - https://support.chaos.com/hc/en-us/articles/4528523195537
Then go to Performance > Development/Experimental Stuff and find the setting "Enviro distance". Increase the value to 10 or 100 times higher. The white line should disappear.
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It certainly reduces it but doesn't quite eliminate it. Especially when compared to the VRay documentation somebody linked to earlier in the thread.
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