Hello,
I have an issue with the shadow catcher material. In the screenshot below you see my scene, in there I have a flat box with a lot of lights shining on it (there are suppose to be other things on the box but I can't show that), some of the objects are Included in some lights and others are excluded in other lights. In ALL lights have the bottom plane is excluded except for the light blue plane you see. This light is creating the blue glow, which I expect to see in my alpha channel. But now I get all kinds of shadows and artefacts in the alpha channel. There is also a rectangle showing up in the alpha channel somehow.
Below the first image you can see the alpha channel when I hide all the lights except for the blue plane, this is how I expected it to look because the blue light is the only light that should be affecting the shadow catcher plane.
Is this correct behavior? The obvious fix is to render 2 images but I prefer not having to do that. Btw I'm on corona 4 so upgrading might help but I prefer not to do that just yet.
Thanks!