Ok. I need to model a 2 layer object. The bottom layer must be an opaque layer that does not allow any light through. Easy enough.
The top layer is a glass like material that lets all light pass through with near zero shadow. Easy enough.
The problem is I do not know how two materials act when they are literally touching, and connected, to each other. Imagine a pane of glass face-glued, sandwhiched, onto another pane of glass, but one of the panes is opaque. How would the light in ray tracing work with this kind of connection boundary?
Can I leave a tiny space between the layers, acting like pure air, and get the same result?
Any help would be greatly appreciated.