We could help you out if we knew something about your project. Please reveal layer properties by selecting all layers in you comp that you're having problems with, pressing UU to reveal the properties, selecting the layer with shift chanels applied, pressing f3 to reveal the effects controls and then sending us a screenshot.
Also include your AE version, OS and System info.
Thanks for replying, but I just figured it out! I clicked on all the layers and turned off the "3D layer" property. I was using cs6.11 on a mac mountain lion osx. Perhaps you could explain what I did exactly to make it work, because I'm still kind of confused.
Not without a screenshot of the setup that didn't work. Cmnd + Shift + 3 will take a screenshot.
This is what I mean... Still can't tell a single thing about your project. Dont' worry about the size of the screenshot, just give us some info.
Notice how I'm showing all the pertinent information. You can completely duplicate my comp by just looking at the screen shot.
Seeing that you have blend modes set to ADD it's possible that you have the composition set to Ray-traced rendering.
If so, that would cause the problem because you didn't read the warning that pops up when you enable Ray-traced rendering about blend modes and effects.
I've re-created a comp that works in 3D. It looks like this:
By simply pressing the u key twice I've revealed everything that anyone would need to know about the composition. It makes it very easy to find the problem.