alpha materials not rendered correctly when rendering with select mask

[Batzbenzer]

So I tried to render these trees from my scene by select render mask. I want to apply them seperately in photoshop, so I can edit them out if necessary.
The leaves have alpha channels applied in their material, which Vray now completely ignores when rendering in select mode. Now I have squares around my leaves, which show the background.
Sorry for the horrible screenshot.



Is this a known issue? Is there a workaround? I'm using Vray Next 3.1, on max 2018. I'm rendering progressively.

[hermit.crab]

Thank you for the report. This is a known issue concerning rendering selected with background and opacity mapped objects. It is already logged (internal bug-tracker id: VMAX-2887) for developer investigation. I'll raise its priority. You may disable the background image and, optionally, use the GI environment override to substitute its contribution.

[Batzbenzer]

Thank you for your quick reply. Unfortunately, disabling the background image does nothing good since what's visible around the leaves is the actual scene, Buildings and everything. I can't disable the scene, since the trees receive GI from it and sometimes shadows from the buildings fall on them.

So you're saying I should make the scene invisible and use the GI of some HDRI that's simiar to my scene? That still wouldn't give me shadows on the trees. I can fake these in Photoshop though.