Render mask Issues

[Anonymous]

All,

Anyone else have this problem? I have attached a PDF that illustrates my problem. I show a before render masks and after render masks. Note the before picture shows no blue background bleeding through my surface. After I apply a bunch of render masks to illustrate my site layout, the background starts bleeding through. I know it is related to certain masks, but I can't seem to eliminate the problem by deleting the mask and trying to recreate it. I have also tried to change the "mid-ordinate" distance with no success.

Does anyone have any experience with how to fix this? Any help would be greatly appreciated! We are trying to create 3D-motion path animations of the site so that the "Lay man" can understand what the site looks like.

Thanks!