Cycles Transparent Shadowcatcher

Hi there,

I am actually surprised at how complicated it is to get a clean, separate shadow catcher file output in Blender that includes transparency.

Perhaps I have a huge oversight on how this should work, but for the last 3 hours, I have not been able to find a proper solution, which is why I am asking here.

I have attached an attempt below where I got it somewhat working, but not exactly as seen in the Viewport.

I have read the Blender documentation, and I am aware that having the shadow catcher pass enabled does initially remove the shadow from the rendering, and with it disabled, it uses an approximation.

Thank you in advance to anyone for any help!

Shadow Catcher Blender Artist Forum.blend (3.0 MB)

Here is my composition…I changed a lot of it/ actually, I started from scratch…

One of the problems I saw was that you had your Light Spread down to 3 degrees which is used to make hard dark shadows…

I didn’t change a lot in the rest of your file except I did use an output of PNG as a RGBA at 16bit…

For the light, I changed the spread to 88 Degrees, and unchecked Multiple Importance