The BREAK command in AutoCAD: swap the points and lose the other half

The break command in AutoCAD removes the piece between two points you pick. On a straight line it is simple enough. On a circle there is a rule everybody trips over at least once: swap the two points and the piece that disappears changes completely.

This article measures both cases on AutoCAD 2027 at the Institute, together with a sibling command few people know. For the full set of editing commands, see the AutoCAD for Construction course.

Two points, two objects, and a gap in a line

Autodesk describes it in one line: "Breaks the selected object between two points." The prompts are just three, copied verbatim from the 2027 release.

Select object:

Specify first break point:

Specify second break point:

We drew a line exactly 4000 long, broke it at 1500 and 2500, then measured each piece.

The two pieces come to 3000, so exactly 1000 units vanished — the gap between the two points you picked.

On a circle, the order of the points decides everything

This is the part worth writing down. In fairness, Autodesk does say it, and says it plainly: the BREAK page states "The program converts a circle to an arc by removing a piece of the circle starting counterclockwise from the first to the second point."

The sentence just sits in the middle of a description and almost no tutorial repeats it. We measured it to see whether it still holds on the 2027 release.

We drew two identical circles of radius 700 and broke both at exactly the same pair of points, one at 0 degrees and one at 90. The only difference was the order of picking. Then we read the remaining arc:

The measured rule is short: the command always removes the piece running counter-clockwise from the first point to the second.

Remember that one sentence and the cycle of breaking, undoing and breaking again stops. To keep the quadrant, pick 90 first; to lose it, pick 0 first.

There is a second consequence: after breaking, the object is no longer a circle but an arc. We read the object type and got ARC in both cases. A filter searching for circles will no longer find it.

Breaking at a single point, with no gap

Very often you do not want to lose anything at all, only to split one line into two. AutoCAD has a separate command for that.

We measured BREAKATPOINT on a line 4000 long, split at 2500:

The two pieces come to exactly 4000. Nothing is lost; the line is simply two objects sitting end to end.

The old way to do this was to run BREAK and answer the second point prompt with @, meaning the same point again. That still works, but the dedicated command is shorter and harder to get wrong.

Three ways to call it

The alias is BR. All three routes reach the same place.

Beside the Break button on the ribbon sits another for breaking at a point. The two icons differ only in whether there is a gap.

The First point option is worth the extra keystroke

The real prompt carries an option this article has not mentioned yet, because it only appears when you select the object with the mouse.

Click a line to select it and that very click becomes the first break point. Convenient, and easy to be a few millimetres out.

The First point option fixes exactly that. Autodesk describes it as "Overrides the original first point where you selected the object with a new point that you specify." You select the line anywhere convenient, then state the break point precisely.

The habit worth building is to always use it when the break has to be accurate. Pick the line wherever it is easy, type F, then snap to the exact point. One extra key removes a whole category of error.

Where the pick lands when you miss the line

A practical question, because a mouse rarely lands exactly on a line.

AutoCAD does not complain. It takes the perpendicular projection of your point onto the line and breaks there, so a slightly wide click still gives a sensible result.

One case needs care. Click well past either end and AutoCAD projects onto the nearest end, so the result is that everything from that end to the other point disappears. That is a quick way to shorten a line without reaching for another command.

For accurate breaks, turn object snap on and snap to an intersection or a midpoint. Object snap is covered in our article on object snap in AutoCAD.

When the object type will not break

Not every object can be broken. We tried breaking a line of text and AutoCAD answered with a short line, copied verbatim.

Object can't be broken

It repeats that every time you pick an invalid object and returns to the selection prompt rather than ending the command. Knowing which object types the break command in AutoCAD accepts saves a good deal of clicking at things that will never respond.

The principle behind it is easy to remember, and it comes down to object type: the command only breaks things that have the shape of a line. Lines, polylines, arcs, circles, ellipses and construction lines all break. Text, blocks, hatches and associative arrays do not, because they are not a line but a composite.

To break anything in the second group you must explode it first, and exploding costs you whatever made it composite. For a block that is usually too high a price; editing the block definition is the better route.

Construction lines are the most interesting case in the first group. Break an XLINE and what is left changes type entirely, to RAY. We measured that in our article on drawing straight lines.

BREAK compared with the trim command

Both shorten lines, so they get used in the wrong places.

The rule for choosing: if a crossing line already exists, reach for the trim command, because it cuts at the exact intersection. With nothing to work from, use BREAK.

The classic case for BREAK is a gap where one service pipe crosses another on a services drawing. There is no boundary to trim to, only a need for a tidy gap in the right place. Lengthening lines is the reverse, covered in our article on the extend command.

Where a deliberate gap in a line actually matters

Breaking is not tidying for its own sake. Three places in a real drawing set need a gap that nothing else provides.

Services crossing. On a drainage or ducting layout, one run passes over another and the convention is a small gap in the lower one. No boundary exists to trim against, so a break is the only clean way.

A break line on a section. Where a long member is shown shortened, the two halves must genuinely be separate objects so the break symbol sits between them without either line running through it.

Grid lines under a title block. A grid line that runs under annotation reads badly. Breaking it either side of the text leaves the annotation legible and the grid still readable.

In all three the gap is deliberate documentation, not an accident, which is why leaving it to a trim against a hidden boundary object is the wrong habit. The gap belongs where the drafter puts it.

Three things often repeated that are not true

Frequently asked questions

What is the alias for the break command?

BR. Two letters and Enter.

I broke a circle and lost the wrong piece.

Undo and repeat with the two points in the opposite order. The command always removes the piece running counter-clockwise from the first point to the second.

How do I split a line without leaving a gap?

Use BREAKATPOINT. We measured a 4000 line split at 2500 and got pieces of 2500 and 1500, exactly 4000 together.

Where does it break if I miss the line?

At the perpendicular projection of your point onto the line. Click well past an end and it projects onto that end instead.

Should I use BREAK or TRIM?

TRIM when a crossing line already exists, because it cuts at the exact intersection. BREAK when there is nothing to cut against.