Template:CustomizingDrawCommandBehavior

• The volume of blocks that can be drawn at once can be limited per-rank. See "Draw limit" field on ConfigGUI's Ranks tab. If you are editing config.xml manually, set the "drawLimit" attribute on the <Rank> tag.
• Being able to undo a command requires storing a backup of an area of the map. This may take up significant amounts of memory. By default, fCraft limits /Undo to the first 2,000,000 blocks that are drawn. You can change this (or remove the limit entirely) via MaxUndo config key.