Emission Object is in front of every other object Hello. I have 2 objects here, the dark cube is a diffuse black color, the white cube is an emission. I have these objects in different layers and have set the render layers up, so I can blur the white cube only.

I try to add these 2 render layers together and the cube is always in front of the black cube. I tried using the less than math node, but using it prevents me from blurring the emission cube.

I would love to know what I am doing wrong here. Any help would be greatly appreciated.
Please consider using the [alpha over node].

For transparency in Cycles render use Panel Film Transparent.



[ Alpha over node ] respects transparency alpha.  In your example opaque black cube would be opaque over all parts of the blurred white cube.

Alpha is transparency and its effects are only visible by compositing two or more layers.

In the image above the white emission cube in layer 2 is blurred.  The sphere and yellow emission cube are in layer 1.  Yellow emission is to increase legibility of explanation.

Two render layer specifications use different visual scene layers in the image below. (Layers and Scenes have some difficult terminology in Blender which could be improved)



3D Views with object visibility in layers in the image below.



Note the checkered background for transparency. Using [object index] is a complement or replacement to layers.