Coinciding objects on different render layers having alpha problems in Cycles

Support Compositing and Post Processing
1

Hi, I’ve been struggling with this and I know there has got to be one checkbox I am missing…

I am setting up an animation where an existing object will fade out to be replaced with another very similar object. I’ve tried 1) animating a transparent BSDF on each object and 2) using a z combine with set alpha in scene compositor. In both cases the two objects have some coinciding faces and this is causing the color to be pure white wherever this occurs even though one of the objects has a full alpha applied.

I have worked around by offsetting the object by .001 x and z and from what i can tell, the visible shift is not perceived at this distance but I would like to find out why this just doesn’t work. There didn’t seem to be a problem in BI with this from my little experimenting in the past.

Thanks in advance! (i have the blend but it is huge. I can send a simple example if needed)

2

Thanks in advance! (i have the blend but it is huge. I can send a simple example if needed)
Why not do that anyway rather than someone having to ask for it ?

3

Ok, I got it. Well, I’ve somehow made some progress on the white overlay problem. I am having trouble with the uploader thing so no blend.

Can you work with screenshots maybe? here are my nodes frame 1:

frame 96:

but the problem comes in with the transition, frame 48 e.g.:

As you can see with the background image there is now just a milky gray everywhere until it gets fully through the transition. So maybe there is a better more elegant way to acheive this transition. I really want to try to avoid setting the keyframes for each individual material transparency because there are just too many to keep track of.

Thanks!