Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] Bug Reporting => Topic started by: fobus on 2025-06-26, 20:47:48
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There is a big problem with Volume Effect in CoronaSky in Corona 13 (in Corona 12.1 it is ok). In Corona 11 we can turn on Volume Effect and use it with every environment map but in Corona 13 we can't do it. It is a big problem to migrate all previous scenes to Corona 13 because of this. Is there any way to turn this behavior on in Corona 13?
I've attached scene with this problem. If this scene opened in Corona 11 it will have Volume effect renderable, but in Corona 13 it is not renderable.
Corona 11/12.1
(https://imghost.online/ib/nqFQxhYRsaGLPVy_1750963408.jpg)
Corona 13
(https://imghost.online/ib/jlgMGht67MgDVwJ_1750963525.jpg)
Scene
https://limewire.com/d/TEHaR#ahapplS6LQ (https://limewire.com/d/TEHaR#ahapplS6LQ)
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Hi,
I have checked the scene.
The issue seems to be in CoronaSelect map, as the one used in your scene simply cannot have 0th map selected (any other than Map 1), even when done manually - it switched back to Map 1, which is black color.
Interestingly, newly created CoronaSelect maps work fine.
Workarounds are using Sky map as Map 1 in CoronaSelect map (Environment) or creating new ones, if that fits.
This is reported now and I will definitely keep you posted when this gets fixed.
Thanks for reporting it.
(Report ID=CMAX-1737)
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Map 0 is wired to CoronaLight target custom properties. This was no problem in Corona 12.2. The main problem is that Volume effect have no effect other than with CoronaSky active, when in pre 12.2 it was possible to use Volume effect with any HDRi freely.
In attacheŠ² file you can find newly created CoronaSelect map with the same problem.
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when in pre 12.2 it was possible to use Volume effect with any HDRi freely.
this - having CoronaSelect with e.g. Sky map with volume effect and some HDRI, and volume effect from CoronaSky being present in HDRI, even when not selected - was widely considered a bug and has been fixed. What if volume effect is not wanted for the HDRI?
For the select map taking Map 1 even when another is selected - this seems a separate/older-than-v13-maps bug, yes.
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when in pre 12.2 it was possible to use Volume effect with any HDRi freely.
What if volume effect is not wanted for the HDRI?
It was no problem to set it to zero value then. So we use this "bug" in all our scenes to enhance aerial perspective and all scenes now unusable in C13. It's unfortunate. No way to use it as "legacy" mode?
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when in pre 12.2 it was possible to use Volume effect with any HDRi freely.
What if volume effect is not wanted for the HDRI?
It was no problem to set it to zero value then. So we use this "bug" in all our scenes to enhance aerial perspective and all scenes now unusable in C13. It's unfortunate. No way to use it as "legacy" mode?
I get that it could have been used as a feature, but what if you have two sky maps, one with volume and one without. In that case the volume would affect the other sky map and HDRIs. It is a clear bug which is now resolved.
I am not sure what your workflow is, but I would recommend fixing the scenes so they follow the fixed/correct behavior, as you open and decide to migrate them to v13. Hopefully the tweaks are not much. E.g. there can be new features coming to sky map and supporting this "feature" would possibly affect the new ones too, which is definitely unwanted.