[Polyxo]

In fact that was my first time with this light/material conditions, but it seems the best way is to live a tiny gap between all panels. It looks like in real world and all this Nd, attenutation stuff have chance to deal as in real life.

Thanks Zdeno, that's what expected too.
Sometimes I think Maxwell should offer dealing with this kind of fit-tolerance for us on a per mxm-basis for us.
So that the input meshes get offset a tiny tiny distance at rendertime while the user can leave the input-geometry untouched.
This probably could help in many scenarios where users deal with dielectric/sss materials.

[zdeno]

I am not sure If i understand You well ,

but every transparent object with Nd different than 1 have to has some volume. Because light ray have to meet at least 2 faces to know where to stop get attenutation for counting, so If window glass are 1 sided polygon there will ge almost completlly dark inside the house.

when camera and light is outside the building it will give us almost black glass with well apparent reflection of surrounding background.

even better is if light is outside the building and camera is inside ( glass is still one face only) so light are all time attenutaded, like room in building is made of glass, like this flies melted in glass or plastic.

I am not so sure if solution for proper glass offset is in .mxm I rather want to have full control with mesh , smoothing groups, chamfer edges, it is just fun to tests.
In 3dmax there is very cool modykicator to make box from plane in one step it is SHELL . fast and good.

In those pictures above I modeled panels as box placed side to side with about 1cm gap (like in real world) not bothering any kind of concrete to fill this gaps
It could be possible to make some stripped texture to play with transmitance, but don,t think this gaps could be better.

[Polyxo]

Hi zdeno,
I was not thinking of people who visualize other people's work and create a simplified
render-optimized model from scatch.
But I was thinking of Product-Designers who typically model to -to fit -without any gaps between parts.
When such a (Nurbs) model gets rendered the render-meshes will always touch or even slightly intersect
which as we know can create problems with Dielectics/SSS materials.

For complex objects it could be a tedious and a destructive task to adjust each part of the model accordingly
therefor I was imagining a special flavour of Displacement which performs an ever so slight positive or negative
Offset at rendertime.