Last updated July 28, 2026
BreakPoint splits an object at a single point without removing anything. Type BP, pick the object, pick the point, and what was one line is now two lines meeting at that spot.
AutoCAD can already do this. The BREAK command has a First point option, and picking the same point twice breaks at zero length rather than cutting a gap. The trouble is the keystrokes: BREAK, select, F, pick, pick again — and getting the second pick exactly on the first, which usually means typing @ to reuse the last point. It is a small piece of friction that you meet several times a day, and this routine removes it.
The whole routine, and why it is worth reading
This is a five-line file. It selects an object, asks for a point, and calls BREAK with the First point option and that same point given twice. That is all there is to it, and the value is entirely in the keystrokes it saves.
It is worth reading precisely because it is so small. If you have been meaning to write your own AutoLISP and have not started, this is a complete, useful, working program that fits on a screen — and it is a demonstration of the most productive thing a beginner can do with the language, which is not writing clever geometry but wrapping an existing command so it takes fewer steps. Every line carries a comment explaining what it does. Our first AutoLISP lesson covers the ideas it uses.
It gets one important thing right that longer routines often miss: both its variables are properly declared as local, so it leaves nothing behind in your drawing session. What it does leave out is an error handler and undo grouping — cancel it partway through and you get AutoLISP’s standard error message rather than a tidy exit. Neither matters much for a command this short, but it is worth seeing what a more careful routine adds — compare it with ROUGHEN, which saves and restores every setting it touches, including from inside its own error handler.
Command reference
The command is BREAKPOINT. The listing describes it as BP, which is what most people would want to type — but that short form is not in the file. If you want BP, add a command alias in your PGP file pointing at BREAKPOINT, or add a two-line wrapper to the LISP file itself.
How to load it
Unzip Breakpoint.zip and load breakpoint.LSP with APPLOAD, or put it in the Startup Suite. A routine whose entire purpose is saving keystrokes is only worth having if it loads automatically. Our AutoLISP guide covers loading.
Step-by-step usage
- Type BREAKPOINT.
- Pick the object to break. There is no prompt for this step, so pick straight away.
- At “Specify Break Point:” pick where you want the split. Use an object snap for accuracy — intersection or midpoint are the usual ones.
- The object is now two objects. Nothing is removed, and both halves keep the original’s layer and properties.
The break point does not have to be exactly on the object — AutoCAD projects it to the nearest point on the line, which is the standard BREAK behaviour. Snapping is still better practice when the split has to land somewhere specific.
Compatibility notes
There is nothing here to break. It calls AutoCAD’s own BREAK command with options that have been unchanged for decades, and uses two of the most basic AutoLISP functions there are. It should work anywhere.
No dialog boxes and no Express Tools calls, so nothing in it requires the full product; LT users on LT 2024 or later, the release that brought AutoLISP to LT, should be able to run it. See what runs on AutoCAD LT.
Download
| Name: | BreakPoint |
| Description: | Breakpoint.lsp is a simple lisp routine that allows you to simply type in “BP” at the command prompt and start the break command it begins the break command to break an entity at a point of your choosing. |
| Type: | AutoCAD AutoLISP Routine |
| Author: | Anon |
| File Size: | 1 Kb |
| Cost: | Free |
| Worked on: | AutoCAD |
| Download File: | Breakpoint.zip |
Related routines
- DOF — another single-purpose shortcut, this one for offsetting both ways at once.
- Join 2 Polylines — the opposite job.
- Best of LISP collection — more short utilities worth reading.