LuxCoreRender Forums

I 'm rendering some stuff that require heavy compositing and extensive use of Alpha mask.
I need my background to be rendered as transparent but i've a very usefull flat plane reflector in the background.
So when the alpha is computed my flat wide background
surface is included making the alpha mask not transparent at all.

So i need a method to exclude the surface from alpha calculation.

You could use object ID mask AOV to get the mask of the flat plane reflector background and than post-process the alpha mask however you want Assuming you are not doing an animation

Dade wrote: ↑Mon Feb 10, 2020 7:35 pm You could use object ID mask AOV to get the mask of the flat plane reflector background and than post-process the alpha mask however you want Assuming you are not doing an animation

Sadly this is what we are going for (animation). But i've found a simple trick by using ""Visible to camera""" flag in a separate render layer and it work