How to make windows

Hello. I was wondering how to make windows, like the ones seen in E1M1 of Doom? The problem I'm having here is that with my window attempt, players can just crouch then jump and get outside! Please help me...

Make them higher or use impassable lines or disable jumping in MAPINFO.

The ones in E1M1 use impassable lines so that you cannot walk through them. You can still shoot through them.

Going into line mode and edit the properties of the lines and select the check box for "impassable"

Don't forget "block monster" if you want to still shoot through them! :)

^ ??? - The "Block monsters" flag merely makes monsters unable to walk through linedefs with this flag set. It doesn't affect either projectiles or hitscans, and it doesn't have any meaning on lines which already have the "Impassable" flag.