An Area (region) with a Hole
Many PCB circuits have areas of conductor with holes cut out of them. The power and ground planes actually will have many many holes.
Below you can an example where we have created a simple square region with a hole in the middle.
The 3Di Description of this Region with Hole
When an extrusion has more than one "entity" the first entity is the surrounding parent and all entities that follow are assumed to define cutouts in the parent.GEOM <-- start of a geometry OBJECT 4 <-- object property (from table) COLOR 8 <-- color property (from table) EXTR 2 1.08 1.2 <-- extrusion of two entities from Z=1.08 to Z=1.2 2DPG 4 <-- 2D polygon with 4 vertices ... (parent) -3.69 -3.08 -3.69 3.08 3.69 3.08 3.69 -3.08 <-- X1 Y1 X2 Y2 X3 Y3 X4 Y4 2DCR 0 0 1.5 12 <-- 2D Circle X,Y radius, number of sides ... (child)