Hello guys please help, i was working normally yesterday on the project and today the roof disappeared, i tried to open backup file and its same there, when i open a backup file it shows the roof in the beginning on section layout, but when i go on other sections and elevations it doesn't show up, i don't remember deleting it accidentally, also i think its still there because the walls are shown as trimmed to the roof, please help me guys, I'm using Archicad 17