My model was using a plane as a shadow catcher in blender 2.79.
I turned off glossy and difuse for the plane.
Set the render settings to transparent and enabled the environment pass.
I am using and environment texture as a background.
The problem comes in compositing when I try to blur the env using the alpha over node.
The entire plane shows up as a dark area and the shadow is gone.
The image and shadow plane work as designed without trying to blur the background.
Not sure but you could put a plane with hold out material behind the foreground… hmmm I guess that means you would need to render with transparency though.
I did render with transparency, the image with the shadow catcher works as planned, but the problem comes when trying to composit them both together and trying to blur the env node. My original post shows the first image which was rendered with transparency alone. The second image is when I tried to composite them together.
I think that you need to grab the background from another render layer so that the shadow catcher isn’t acting as an occlusion (thats why its a big black blob)
