Changing "two sided" value in 4000+ materials

[FilipWåhlin]

I am trying to port a map into ue4, where all surfaces are supposed to be two sided. By default UE4 sets the "two sided" option in materials to false, when changed to true the surface displays correctly. Is there a way to change all 4000+ materials to "two sided" at the same time or change the default value for the "two sided" option to true?
It would have been possible to invert all normals if not many of the are displayed correctly from the start, and many aren't.

[MostHost LA]

Bulk edit options possibly.

but why so many materials and not instances?

in either case the performance would probably be twice as bad (not quite but in theory you will then be rendering twice as much).

[presto423]

I think there's an option for it in either Project Settings or General Settings.

[Bits360]

I am trying to port a map into ue4, where all surfaces are supposed to be two sided. By default UE4 sets the "two sided" option in materials to false, when changed to true the surface displays correctly. Is there a way to change all 4000+ materials to "two sided" at the same time or change the default value for the "two sided" option to true?
It would have been possible to invert all normals if not many of the are displayed correctly from the start, and many aren't.

Why would you have 4000 materials ever?

[ThiloN1987]

You could also make a editor utility widget/script for that.