Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: wardy_mk on 2023-05-04, 10:18:02

Title: Rendering out with alpha channel that catches the shadow detail
Post by: wardy_mk on 2023-05-04, 10:18:02

Hello. I have a job I'm working on. I'm rendering out individual items of office furtniture etc. The file is super simple. A desk (or whatever) then a 'floor' item, a camera, then a HRDI studio. I rendered them out and supplied them to the client. Now, because she's no good in photoshop / Indesign etc she's asked me to provide them on a transparent background.

I'd usually do this with an object buffer and perhaps mess around with the background so it's set to overlay etc but she seems to want it 'transparent'. This means I'll lose my nice shadows on the floor and everything will look 'floating' and a bit rubbish.

How would I be able to render out the items with a separate 'shadow on the floor' layer in Corona?
Thanks folks, super new to this.

Title: Re: Rendering out with alpha channel that catches the shadow detail
Post by: Beanzvision on 2023-05-04, 10:35:46

Hi there,

You can use the shadowcatcher material for this and set it to ''for compositing''. Put a compositing tag on the HDRI/Sky and uncheck ''seen by camera''. Render the object and save it as a png. When opened in PS you will have the object and shadow as needed.

Setup:
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39962.0;attach=182768;image)

Outcome:
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39962.0;attach=182770;image)

Hope this helps! :)

Title: Re: Rendering out with alpha channel that catches the shadow detail
Post by: bnji on 2023-05-09, 00:43:08

Hi there,
As Beanzvision already said, use the Shadow Catcher shader.
You can look at the knowledge base: https://docs.chaos.com/display/CRC4D/Corona+Shadow+Catcher+Material
I hope this helps.
Kind regards.

Title: Re: Rendering out with alpha channel that catches the shadow detail
Post by: steppes on 2023-06-27, 10:52:01

I used this method for my current project, but I mentioned that the rendertime increases significantly.

In standard (shadow catcher is always solid) and no tag on the sky the rendertime is about 1 minute
with shadow catcher in compostiting mode, the rendertime is about 5 minutes
with shadow catcher in compostiting mode, an rendertag on the sky the rendertime is about 12 minutes

BTW does the beautypass look pretty strange. Is this intended? (Corona 10)

Title: Re: Rendering out with alpha channel that catches the shadow detail
Post by: Beanzvision on 2023-06-27, 11:16:34

Hi there, are you able to share a test scene for us at all?