A line appears when two planes are not perfectly coplanar or if there is a break between two construction elements of the same material or if there is a change of material.
Christophe - FRANCE Archicad Designer and Teacher Archicad 15 to 27 FRA FULL
OS 11.6 Big Sur - MacBook Pro 2017 - 16Go RAM "Quality is never an accident ; it's always the result of an intelligent effort" John Ruskin
@LeeJaeYoung Please add a signature with the version of AC you are running and platform win/Mac? This may be an old bug. Does it happen at all corners?
Apple iMac Intel i9 / macOS Sonoma / AC27UKI (most recent builds.. if they work)
