Volume Materials and opacity light sources Produces wrong results

Corona Corona for 3ds Max Issues
1

Hi, we have a problem with corona when using light sources (real lights or self illumination)
If you have a global volume material or a volume effect on the scene the opacity maps will have a halo effect visible on the diffuse channel and very visible on the alpha (i have tested cliping the maps in all ways) I have a small scene attached to see the problem.

WM-Screenshots-20220722085315.jpg
WM-Screenshots-20220722085315.jpg1024×488 73.6 KB

WM-Screenshots-20220722085338.jpg
WM-Screenshots-20220722085338.jpg1020×490 74 KB

WM-Screenshots-20220722085403.jpg
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Bug Corona.7z (1.37 MB)

2

I may be wrong, but it looks like “Transparent materials seen through global volume material (volumetric fog) may look incorrect.” described here, the example image with fire:
https://support.chaos.com/hc/en-us/articles/4528311915025-Known-bugs-and-limitations

Can you check if the suggested solution helps in your case?

3

Hi, just tried the solution but what its doing is increasing the volumetric effect to the point nothing is visible and the “bug” is more pronounced, if i lower it the halo disappears but the volumetric effect too.

Deafult.png
Deafult.png964×519 68 KB

Higher.png
Higher.png979×511 65.6 KB

4

I have successfully reproduced and re-reported this issue. Sadly, I did not find any workaround. Perhaps the only option is rendering twice:

  • without the fog effects to get correct alpha channel
  • with the fog to get the expected beauty

Sorry for the inconvenience. I will report here if we find any reliable workaround or when this is fixed.

(Internal ID=956670590)