AutoCAD Wall Opening LISP: Door and Window Gaps in One Step

Opens a gap between two points in a double-line wall and draws the jamb lines.

This AutoCAD wall opening LISP adds the WALLGAP command. It asks for the two lines of a double-line wall and the start and end points of the gap, then cuts both wall lines between those points and draws the jamb lines that close the wall on each side.

Your points don't have to be exactly on the wall lines; each point is projected perpendicular onto both lines. That way the gap lines up on both faces whether you click the centerline or one face of the wall. The jamb lines go on the layer of the first wall line.

Done by hand, this takes two BREAK commands and two LINE commands. WALLGAP does it in one command and one undo step.

How to use it

1. Load wallgap.lsp with APPLOAD and type WALLGAP.
2. Pick the first line of the wall.
3. Pick the second line of the wall.
4. Pick the start point of the gap.
5. Pick the end point of the gap; both lines are cut and the jambs are drawn.

Notes and tips

• The wall lines must be LINE objects. Polyline walls, such as those drawn with DOUBLELINE, need to be exploded first.
• Both gap points must project onto both wall lines within their length; otherwise the tool warns you and does nothing.
• It does not insert a door or window block; it only opens the gap.
• For an exact width, snap to the start point and type the end point as a relative coordinate such as @36<0.

Frequently asked questions