Butterfly exact size

[imix01]

Hello,

I'd like to build an 12'x12' butterfly frame, but I don't know the exact sizes.
I think I have to build bigger frame than the silk.

How big is a manufactured 12' x 12' silk, like manfrotto or matthews, etc. ?

Thanks: Imre

[puredrifting]

12'x12' butterflies measure approximately 11'8"x11'8".

Dan