Glass [completely transparent] renders black unless GI is enabled on it's properties

[3DMK]

Just started using RT & did a search with no results so forgive me if this issue has already been raised befor.

Glass that is completely transparent renders black unless GI is enabled on it's Vray properties.

I usually turn off GI in vray properties for glass to speed up render time, as it's completely transparent and has no real effect on the GI solution. [By the way if that is wrong or completly stupid then please let me know I'm a fool]
From my experience turning off GI for glass doesn't seem to effect the end result in the production render although in RT the glass is going completly BLACK & solid

Any ideas??

Cheers

[vlado]

Do you mean the "Visible to GI" option?

Best regards,
Vlado

[3DMK]

Do you mean the "Visible to GI" option?

Best regards,
Vlado

Yes Vlado....that's the option I had turned off

NOTE* I also had the Generate & recieve options OFF as well although I guess their not doing much if the Visible to GI option is already OFF.??

Cheers