RS Shadow passe

[AlexC]

Hello
I have a scene where a character is being integrated into a BG plate.
I recently upgraded C4d and RS and noticed that the BackPlate option was gone in the Dome Light, and I heard it was moved to the Camera object, but I don't see it anywhere (I have a solved camera from a Motion Tracker).

In the meantime, I rendered my object by itself and added a disc to create a shadow catcher. I put the RS object tag on the disc, enabled the matte options, etc My preview render shows that the shadow catcher is working.

However, if I render out the object and the disc without the background, I end up with the disc visible in my alpha channel.
Do I have to use AOV's for this? I assumed that it would be possible just to get the shadow in the alpha channel and that the disc itself would become invisible.
Test scene below
https://www.dropbox.com/s/zba4as9exzcq57g/ShadowMatteIssue.c4d?dl=0

Thanks for any pointers!

[Dr. Sassi]

Hi AlexC.

Thanks for the file, but the camera in question was not included. I assume it is not an RS Camera.

Create a copy of the camera, go to Main Menu> Window> Customization> Command Manager.

Call up an RS Camera Tag

In the Attribute Manager, while the tag is selected, you will find an option "Conversion". For that, version 2023.2 is required.

If that doesn't work, send a file to connect the tracked camera via XPresso to a new RS Camera. (Matrix, the field of view, etc.)

All the best

[AlexC]

Thank you Sassi! That worked!

Out of curiosity, if I decide to render without the background and just the subject with the contact shadow, what is the procedure to avoid the geometry of the shadow catcher from appearing?

Thanks!

[Dr. Sassi]

Thanks for the feedback, AlexC.,

Please have a look here:

CV4_2023_drs_23_RSsc_01.c4d

Let me know if you need something else. I'm happy to look into it.

Cheers

sassi

[AlexC]

Amazing, I had the "affected by Matte lights" box checked, and that was causing the issue strangely...

Thanks!

[Dr. Sassi]

Thanks for the update, AlexC.

Yes, that is a tricky one. It requires deciding what light hits what based on the light in the source. I think default off is good, but well, case by case…

My best wishes.