shadow catcher with Cycles?

[cekuhnen]

Hi there,

does anybody maybe know if it might be possible with Cycles to create a material that only catches the shadow and leaves the rest of the material transparent?

Claas

[cekuhnen]

ah darn - compositing tricks would be too much for the students to deal with.

[Alain]

@cekuhnen

ah darn - compositing tricks would be too much for the students to deal with.

I guess you use it for product design presentations and you want to place the productrenderings on various backgroundimages.

Based on the obove tutorials I made a Compositor-Setup to save the Rendering with Alphatransparent shadows.
This way you can import the Rendering to Photoshop and put it on what ever you want.

Once the Compositing is set up your stundents can render every product they want and they don’t have to deal with the Compositor every time
I hope it’s useful for you.

Kind regards
Alain

[Noke]

@Alain

I guess you use it for product design presentations and you want to place the productrenderings on various backgroundimages.

Based on the obove tutorials I made a Compositor-Setup to save the Rendering with Alphatransparent shadows.
This way you can import the Rendering to Photoshop and put it on what ever you want.

Once the Compositing is set up your stundents can render every product they want and they don’t have to deal with the Compositor every time
I hope it’s useful for you.

[ATTACH=CONFIG]210074[/ATTACH]

Kind regards
Alain

Aloha Alain, are you using lighs instead of a plane with an Emission Shader under Cycles as it was under BI?

[Alain]

@Noke

Aloha Alain, are you using lighs instead of a plane with an Emission Shader under Cycles as it was under BI?

I don’t know how it was in BI, but I use standard Lightobjects, no light emitting geometry.

Kind regards
Alain

[eknightGER]

@Alain

I don’t know how it was in BI, but I use standard Lightobjects, no light emitting geometry.

Kind regards
Alain

Hi Alain,

would you please be so kind as to share the blend file for this setup? I am replicating the very same compositing and I am not getting the same results and I have no clue why. I am also using blender 2.65.5. My result is broken (I get wrong / darker shadows and no transparency at the end (despite the compositing node showing it). Thank you very much again

[Alain]

@eknightGER

Sure, here it is:
Transparente_Schatten_00_030113.zip (78.9 KB)

You have to save the Rendering in a Fileformat that contains Alphatransparency (PNG for example).
And don’t forget to activate “PNG with Alpha” in the Filesavingoptions.

Kind regards
Alain

[rhunecke]

Hoping this Thread is not already considered dead:

I read across different solutions to create a simple Shadow-Catcher material inside Cycles. Though your solution is quite simple it won’t work with Mesh-Lights. I’m using 2.66a. I think there must be a difference between calculating shadows of standard light sources and mesh lights.

Any thoughts on this?

Thanks again Alain, it’s a great time saver anyway, as long you don’t want to use mesh lights

Edit:
Read across the Bug Tracker to find this:
http://projects.blender.org/tracker/?func=detail&atid=498&aid=34272&group_id=9