I have a simple animation where some objects move behind other objects. To make them translucent as they become blocked from view, I render them on a second layer (using the compositor) that makes the moving objects translucent, but only when passing behind other objects. This creates a see-through effect.
Initially, these objects are supposed to be invisible until frame 100 is reached, after which they become full visible and start moving around. The problem is that the translucent layer is rendering the objects as fully visible (though translucent due to the translucent-layer settings) even when their alpha values for the material is zero. So, what I wind up with between frames 1 to 100 is a ghost image of the objects when they are supposed to be invisible.
If I remove the translucent layer, there are no ghost images.
Any ideas would be greatly appreciated.