Reflection catcher?

[bigskyedit]

I know this has been asked numerous times, but I just can't seem to find a good solve. Is there a good way to catch reflections just like a shadow catcher? Any suggestions would be appreciated. Thanks.

[Terryvfx]

Correct me if I'm wrong my memory it's a bit fussy but I believe you can use the Render Layers and set it up so that you get reflections and shadows for say a Floor Render Layer.

[bigskyedit]

Thanks for the response. Yes you are correct, but I'm not getting good results with the layers for composite later on. I guess I will keep trying to make it work.

[Terryvfx]

Are you using After Effects for comp? if you can post the layers that you are getting out of Octane just to take a look.

[bigskyedit]

Thanks for your help. But I finally figured out a workaround to get it to look right.

[jayroth]

Always a good idea to share your solution. Doing so helps the community.

[bigskyedit]

You're right Jay.
So It seemed like a simple thing. I have this image of a basketball court.

And I wanted to put a reflective sphere on the court. So I need the sphere to reflect the environment, but also reflect the court it was sitting on. And we should see the ball reflected into the court.
I did all of this rough, just to get the workflow for an upcoming project so I can figure out the layers I need to make it work with the animation. So I made a reflective floor which I camera projected the background image on. I also made a Visible Environment to get the scene reflections onto to the sphere. Got it all to work and look decent enough in Octane.

I also made the floor mask away so that I could blend the beauty if I wanted to.

So I was able to use this render out beauty and composite fine in After effects, but I wanted more control over each pass and didnt want to use that whole floor. So I wanted the ball on its own, and then be able to put in the shadow and reflection separately so that the floor was the real floor. This was where the problem was. Using the Render Layer way, the black shadows pass and the reflection layer were both totally different when composited. Even just using a Shadow Catcher was giving me a different result, becuase it wasnt a reflective floor.
This is what the shadow catcher looked like.

But after some playing around with the beauty passes the best result I got was rendering a Beauty pass, Reflection, Shadow and a Cryptomatte pass and was able to composite it to work.

Ball with matte (normal matted with Cryptomatte, some color correction)
Reflection (Screen, some color correction)
Shadow (Multiply)
BKG image

Final Comp

Again, Lighting wasnt perfect, it was just a test to get the workflow to work and I feel like it did. What I do wish Is that I didnt need the full floor reflection, because its getting unnecessary reflections from the environment I added. But I wasnt able to use just the Render Layer reflection pass. It didnt look right, especially with the wrong shadow as well. Anyway hope this helps.

[increon]

Hi,

I am currently struggling with the same issue:
viewtopic.php?f=30&t=76484&p=393500#p393500

The thing is: The reflection layer isn't usable if it already contains the background image or some HDRI being reflected. But I think you used the correct description: Reflection Catcher. That's exactly what I need (and a possibility to exclude environment tags from reflections/refractions).

Best regards
Emil

[bigskyedit]

It seems using the Render Layer option is the best way to do it for now.

In some good news, I'm working with the 2021 beta now and there might be a solution