CoronaLightMtl opacity bug using CoronaSky Volume Effect

[nathanwruck]

I use 3dsmax 2024 and I like to use mountain backgrounds with CoronaLightMtl and I use opacity map to cut out the shape of the mountains to use the sky of CoronaSky, but when using the Corona Sky "Volume effect" it affects the material where nothing should appear because it is 100% opacity... Fixing this would be important... Thanks

[Avi]

can you share the scene? You can also share it privately by starting a ticket with us: https://support.chaos.com/hc/en-us/requests/new

Note: you can also share images showcasing the problem (renders, viewport screenshots, material setup) here so that we can understand better what is going on

[nathanwruck]

You can see that there is a lighter rectangle where the Volume Effect is affecting the opacity of the mountain.

[Avi]

Hi,

I was able to reproduce this issue on my end. I have logged this in our system.


(Report ID=CMAX-1260)

For now, you can use corona physical material with self-illumination or use Corona color correct to increase exposure of your backplate as a workaround.

[pokoy]

...
For now, you can use corona physical material with self-illumination or use Corona color correct to increase exposure of your backplate as a workaround.

But... how would increasing exposure of the backplate help if the area with 0% opacity would *still* render brighter for anything behind it?

I guess the volume effect needs to be looked at in general, it's producing unexpected results in too many cases, especially since problems have been reported for quite some time now.

[Avi]

this issue is only happening with Corona light mtl and not with Corona physical material. You can test it. & there are other cases as well where using volume effect is breaking things but those are different issues. In general, most of these cases are reported and are being looked at.

[pokoy]

this issue is only happening with Corona light mtl and not with Corona physical material. You can test it. & there are other cases as well where using volume effect is breaking things but those are different issues. In general, most of these cases are reported and are being looked at.

What I meant is that it doesn't seem logical to suggest increasing exposure in a CC node specifically since the plane in front will still render brighter. So if you brighten the background up in CC, it'll render even brighter, still.

[Avi]

this issue is only happening with Corona light mtl and not with Corona physical material. You can test it. & there are other cases as well where using volume effect is breaking things but those are different issues. In general, most of these cases are reported and are being looked at.

What I meant is that it doesn't seem logical to suggest increasing exposure in a CC node specifically since the plane in front will still render brighter. So if you brighten the background up in CC, it'll render even brighter, still.

Sorry, I don't understand. I think we are discussing two separate things. Can you explain why would "plane in front will still render brighter" with Corona physical material?