[Data] 0=gutterskin.grf 1=data.grf 2=rdata.grf
In Ragnarok Online, the map is divided into invisible tiles. "Gutter lines" occur every 5x5 or 40x40 cells (depending on the server mechanics) and can cause skills to fail or behave unpredictably if cast directly on the line. Visually see where cells begin and end.
If the line draws but is invisible:
: Some versions also show the splash radius of other area-of-effect (AoE) skills.
edits or third-party tools to visualize these lines directly on the game floor. How Gutter Line GRF Downloads Work
