Alpha Channel with Foliage not working good

[Soluna]

Good morning community,

yesterday I noticed once more that in all of my scenes where I have a transparent background which I wanna replace in photoshop/affinity. I always have an alpha channel which doesn´t seem to be correct. Especially not in areas where I have foliage. I already searched the web for solutions and asked on a 3ds max discord but nothing really worked for me. To better show you what I´m talking about I have a few images here as an example:



I`m mostly using VRay Dome Lights with HDRI but if I recall it happened when using VRay Sun and Sky, too. I´m always rendering 32-Bit .exr-files cause our prof at university wants us to. Is there any elegant way to fix this? It´d be really important for me cause I feel that most of my renderings suffer from that.
I used VRay 5 for the last months and downloaded the Update 1 once it came out.

Thanks a lot in advance!

[fixeighted]

You will need to render against a black background - just make your dome invisible. That'll fix it

[Soluna]

Thanks a lot for your reply! I tried that out in the last 1-2 hours but I noticed that the results look a bit different. I just rendered a small part of the whole image to save some time. As it seems it´s the refractive materials that look completely different. Is there any fix for that? Except for those materials, it seems to work at first glance. I´d need to render the whole image so that I have a better comparison.

[fixeighted]

Check that your glass/water etc shader has enough reflection/refraction depth and that it is set to colour/alpha...should fix it...

[Soluna]

As it seems that didn´t help . I doublechecked both materials, wine and glass. I set the materials to colour/alpha and increased the max depth to 30, 50 and even 100 to try it out but that didn´t change anything. Then I tried some materials from the V-Ray material library. Wine, standard water and orange juice but they all looked bad as well with the Dome light set to invisible. Once I make the Dome light visible again, all those refractive materials look a lot better.

Edit: It seems to work with the swimming pool water though. Once I make the Dome invisible the water still looks the same.

[fixeighted]

Hmm....did you check 'max transparency levels'? Possibly that is either too low or you have the override on...hard to say as I can't replicate it in my simpler test.
Feel free to dropbox a cut down scene and I can see if I spot anything odd.

[Morne]

Add the HDRI to the reflection/refraction override in VRay Environment

[fixeighted]

Oops...forgot about that one. Problem solved.

[Soluna]

The trick with the reflection/refraction override in VRay Environment seems to work! In IPR it looks good already! I´ll let you know tomorrow once my rendering is finished and when I could try out the composition in Photoshop!

Thanks a lot already, you two!!

Edit: Just finished rendering. Everything works perfectly in Photoshop and Affinity!! Thanks a lot again for your help!