Use this procedure to divide linework, AEC polygons, mass element extrusions, spaces, or a block containing any of these objects into two (or more) parts defined by a divide line you draw. The parts on either side of the line are then separately selectable. If a closed-boundary object is divided into two parts using this option, both parts are recreated as closed. If an open polyline in a zigzag pattern is divided along its length, many selectable segments are created.
Alternately, enter the command LINEWORKDIVIDE.
The divided parts of the linework or object on either side of the divide line are now selectable. Note that the divide line is no longer visible once the second point is selected.
Dividing a space object