I tried a tutorial concerning shadow matte,
when the guy applies it on a grid it works directly in his preview
for some reason it doesn't work with me.
the shadow matte passes is rendered and i can composite it, but in the tutorial it is functional directly without compositing like modo shadow catcher.
here is the file…

RAR :
HIP file and background test image

Thanks for helping

I've not seen the tutorial, but the shadow matte is doing what it should in this file. Shadowmatte material sets the alpha channel, only, of your render. You probably don't want your sphere to show up in the render, so you might want to ensure this is rendered as a phantom (look at the render tab of the Geometry node).

here is the tutorial
http://nccasymposium.bmth.ac.uk/2008/ahsan_zohaib/tutorial.html [nccasymposium.bmth.ac.uk]

check from 12:00…he does a render and the shadow matte acts as a shadow catcher …without him compositing anything, it works straight out of the box.

i tried but it didn't work for me

Hi, I have found now your older post about a shadow catcher in Houdini. Did you solve that already? I am facing the same problem now.
Thanks for an answer.
Teresa