layout map with a total footprint of 20 baseplates
arranged in a 5x4 rectangle.
is the amount of table
space that a MOC
takes up. A building may be 1'3" wide by 1'9" long, but the landscaping
that it's built on makes it take up a 2X3 baseplate footprint. Footprints for LEGO
creations are almost always rectangular dimensions. Even when a MOC has a non-rectangular base, people working with it will often refer to its size as the rectangular area that could be superscribed around it.
The coordinator for a collaborative display will often use the footprint sizes of the MOCs that people are bringing to design the layout on the tables beforehand. Similarly, if a group has a set amount of table space and has, for example, a 20" X 40" space that no one has called dibs on, they might offer an area with a 2X4 baseplate footprint for someone to use.