Custom AOV - 'Render Layer Reflection Catcher with Alpha'

[jessestormer]

I know it's been discussed around here many times about wanting an alpha channel on 'render layer reflection' pass
So -- I am trying to set up a custom AOV that would do so... but sadly it partially breaks when Render Layer is on

Here is an image that I hope helps explain...

What I would like to do is use the custom AOV pass as the matte/alpha channel for the layer reflection. But -- The AOV doesn't include the reflective surface when 'render layer' is enabled. But render layer is also required for me to get the reflection pass...

Is there a way for me to still get this Custom AOV with Reflection (center image) , while 'render layer' is still enabled? (without doing two full render passes, that's kind of silly..)


For dark objects on light backgrounds ... you can't just set your reflection to add mode. But I also don't seem to have a way to get out all of the information I need in a single render pass

Edit: Essentially I would love to be able to use/access the Custom AOV as it exists while 'render layer' is off, but while 'render layer' is enabled' -- something like an 'ignore render layer' tickbox would be a great little option to have on AOV passes

[bepeg4d]

Hi,
new 2023.1 Alpha/beta gives you much more freedom on AOVs masking, but it is not clear to me why you cannot use Render Layer reflections + Custom AOV.

ciao,
Beppe

[jessestormer]

Hi,
new 2023.1 Alpha/beta gives you much more freedom on AOVs masking, but it is not clear to me why you cannot use Render Layer reflections + Custom AOV.

ciao,
Beppe

Oh that's awesome, great -- I will check it out!

But my reason is -- the part of the AOV I'm trying to utilize is the reflected matte on the ground plane (to retain the black information in the object reflection) -- but that gets cut off of the AOV pass when 'render layer' is enabled

Thank you!

[bepeg4d]

Ok, but this is expected, I mean, why you cannot use the Render Layer reflections pass?

ciao,
Beppe

[jessestormer]

Sorry for the delay! I didn't notice I got a response, I came up with a few images to help explain.

Essentially (particularly on light-colored backgrounds) setting the reflection to 'add blend mode' is not enough. Part of the compositing is obscuring other reflections from behind the object as well -- where the 'alpha channel' comes in, or even the AOV (including reflection)

The top row shows the render layer reflection being set to add mode, the bottom shows the reflection pass matted with an AOV matte. (the darks in the reflection are just as important as the light)

Example of using the AOV as a matte for the layer reflection pass- but requires two render passes

Thank you! I am hoping this shows how setting the reflection pass to add mode is not enough -- and why an alpha channel for the reflection would be incredibly helpful, or even the ability to render the reflection matte for that object (without multiple render settings/exports)

[bepeg4d]

Ok, now I see your point, but this is something that cannot be change from plugin side.

Try to post your request here:
viewtopic.php?f=9&t=37045&start=530

ciao,
Beppe

[jessestormer]

Awesome, perfect -- thank you for that link

I'll get it added as a wish-list item!