Glass railing.

[vermu]

Hi,

What would you suggest would be the best work method in my situation. I have glass railing in the picture and I am using hdr light to illuminate the scene. When I render the hdr background is seen through the glass railing. But I will change another background in post. And in post there is hdr map seen trhough the glass railing. How should I render the scene so that finally I would see my post background through glass railing?

[Morne]

Did you add the HDRI in a dome light or in the environment or both? Take a look at adding it into the dome light, then look at the affect alpha switch.
There's also the refraction override in the vray environment as an option...