Layer reflection with alpha background?

[naughtypoy]

Hi, Guys. I have a question.

I'm using Octane C4d plugin, Is there a way to render reflection catcher with alpha BG in render layer? Because currently what i got is the render layer will render the reflection on the floor as a separate passes call layer reflection, which is the reflection with a black BG. The problem is when i comp in the reflection in After Effect, I change the blending mode to Scree/Add to get rid of the black BG. But it will also make the black color part of my object disappear. Which is not what i want.
Is there any workaround for this kind of situation?

Thanks.

[bepeg4d]

Hi naughtypoy,
the Reflection layer needs to have a black background, since it needs to be composed in Add mode.
Please, have a look at this other discussion with example scene:
viewtopic.php?f=30&t=62817&p=321359&hil ... er#p321359
ciao beppe

[naughtypoy]

Hi naughtypoy,
the Reflection layer needs to have a black background, since it needs to be composed in Add mode.
Please, have a look at this other discussion with example scene:
viewtopic.php?f=30&t=62817&p=321359&hil ... er#p321359
ciao beppe

Hi Beppe! Thanks for the reply.
I can get the reflection, my problem is because of the project purpose, i have to compose the reflection on a white background, then when i composed in add mode, the black color part of my model will get rid by the Add mode.

[bepeg4d]

Hi naughtypoy,
ok, now I have understood what you meant
With pure white background, you lose all the reflections, not only the black parts:

You need to slightly reduce the luminosity of the white background to see the reflections:

ciao beppe

[jeremyshin]

I'm sorry to re-open that post but I didn't really understand how it works.

I rendered the shadow and the reflection passes of my Render Layer but when I comp in photoshop I get a full white reflection (even with a slighly gray BG). It seems that I can not get back to the original look. You can see the picture attached, showing the live viewer render and the photoshop compositing side by side.

Thank you,
J.

[bepeg4d]

Hi,
what happen if you change the fusion from Screen to Add in PS?

ciao Beppe

[jeremyshin]

Hi Beppe,
It is even worse, see the pic attached
J.

[bepeg4d]

Hi,
please try with 2020.2-RC6, Linear Add 50% seems to work correctly here:

ciao Beppe