Capture Zones in Maps

Ok so I have a map that's almost done, but I want to put some tape around the point to mark the capture zone like on other maps, however I don't exactly know how to do this on the map.

 

Some maps use one of the hazard stripe textures on a brush face (16hu or smth wide), others use overlays (note that some configs disable overlays). You could also make really slim func_detail, or even better, func_brush set to non-solid hazard striped columns to mark the cap area. Maybe look into decompiled maps to see how exactly someone has marked their capture area, or try to be creative and invent a new way