How to draw an arrow in CAD: hands-on MLEADER, PLINE and symbol arrows

To draw an arrow in CAD sounds like one job, but it is really three different jobs sharing one name. Someone asking the question may need a note pointing at a wall, may need a solid arrow showing which way a stair goes up, or may need the view direction arrows at each end of a section line.

This article is written so you can follow along at the machine. Every command comes with a short exercise that says what to type, what the program asks back, and what you will see on screen. To learn annotation and documentation end to end, see the AutoCAD for construction course.

Set up: something to practise on

You do not need an existing drawing. Open a new one and draw a simple shape; the whole article works on it.

1. Type UNITS and press Enter. Set Insertion scale to Millimeters and click OK. This step decides that every number below is a millimetre.
2. Type REC and press Enter. Click anywhere for the lower left corner.
3. Type @4000,3000 and press Enter. You get a rectangle four metres by three — treat it as a room.
4. Type Z, Enter, then E, Enter. ZOOM Extents fits the shape to the screen.

Keep this shape. All four exercises below annotate it.

Draw an arrow in CAD: three meanings, three commands

Before typing anything, work out which of the three you actually need.

The difference sits in the last column. A Multileader is an annotation object: edit the text and the leader follows, and it knows how to scale for plotting. A polyline is geometry only; resizing it is manual work.

Exercise 1 — MLEADER, an arrow that carries a note

This is the command people actually want when they ask how to draw an arrow.

Type MLD and press Enter. The first prompt appears:

Specify leader arrowhead location or [pre enter Text/leader Landing first/Content first/Options] <Options>:

That prompt asks where the arrowhead goes. Three steps:

1. Click the middle of the top edge of your rectangle. That is what the arrow points at.
2. The prompt changes to Specify leader landing location: — that is where the text sits. Click a point up and to the right, about a metre clear of the shape. An in-place editor opens and the ribbon switches to the Text Editor tab, exactly as with MTEXT.
3. Type TUONG GACH 200, then click Close Text Editor on the ribbon, or click into empty space.

You have just made one single object called a Multileader. Select it and check: text and leader highlight together, never separately.

Make a second one for exercise 3: repeat the three steps, point at the left edge of the rectangle, and type CUA DI 900.

The four options in the first prompt only change the order of work, never the result. Type the capitalised letter and press Enter to pick one.

Autodesk documents every prompt on the MLEADER (Command) page.

Exercise 2 — MLEADERSTYLE and the paper-size trap

If the note you just drew is so small you have to zoom right in to find it, you have met the most common trap of this command. Most online tutorials skip it.

The Standard style in a new drawing sets text height 4 and arrow size 4. Both numbers are sizes on paper, in millimetres. Annotate at 1:100 without changing anything and the note comes out exactly one hundred times smaller than you need.

Fix it:

1. Type MLS and press Enter. The Multileader Style Manager opens.
2. Select the Standard style on the left and click Modify.
3. Go to the Leader Structure tab. In the Scale group, set Scale to 100.
4. Click OK, then Close.
5. Type MLD and draw one more note. This time text and arrow come out at a readable size.

An easy rule: the scale factor equals the denominator of the drawing scale. Draw at 1:50, set 50; draw at 1:100, set 100. This field plays exactly the role that Use overall scale of plays in a dimension style.

A multileader style has three tabs, each responsible for one thing. Open Modify again and click through them.

That Content field decides something many people do not know is possible.

Set the content to a block and the door code becomes a readable attribute that can feed a door schedule. Leave it as text and the code is dead text you have to count by hand.

Exercise 3 — aligning notes with MLEADERALIGN

A drawing that looks messy almost always has one cause: the horizontal landings of its notes do not line up, so the text steps up and down like a staircase.

You have two notes at different heights from exercise 1. Line them up:

1. Type MLEADERALIGN and press Enter. This command has no default alias, so type it in full.
2. At Select multileaders: pick both notes, then press Enter.
3. At Select multileader to align to or [Options]: click the reference note, the one already where you want it.
4. At Specify direction: click a point directly below the reference note. That sets the direction they line up along.

Notice this in the right-hand image: the text moves onto one line but each arrow still points exactly where it did. The command only straightens the landing; it never touches the arrowhead. That is what makes it safe to run in bulk.

Type O at step 3 to change the spacing mode. Its sibling MLEADERCOLLECT gathers several notes pointing at one place into a single cluster, but only works when the content is a block.

Run MLEADERALIGN once per area before plotting. It is the cheapest step that makes a drawing look professional.

Exercise 4 — a solid arrow from PLINE and its width

When you need an arrow that is geometry rather than a note — the stair direction arrow, a slope arrow — use a polyline with width.

Draw a 1500-long arrow inside your rectangle:

1. Type PL and press Enter. Click a point for the tail of the arrow.
2. The prompt reads Specify next point or [Arc/Halfwidth/Length/Undo/Width]:. Type W and press Enter.
3. At Specify starting width <0.0000>: type 0 and press Enter.
4. At Specify ending width <0.0000>: type 400 and press Enter.
5. Type @1500,0, press Enter, then Enter again to finish.

You get a long triangle — a solid arrow — and it is one single object.

Start width 0 and end width 400 are what taper the line into an arrow: the shaft begins as nothing and finishes 400 wide. Leave both widths equal and you get a plain thick line instead.

For a thin shaft with a flared head, like a hand-drawn arrow, do it the other way round: draw the shaft at width 0 first, then call W for the last segment only. Within one polyline every segment can carry its own width.

The H option (Halfwidth) behaves identically but takes half the width, measured from the centre line out: enter 100 and the line is 200 wide. Every option is listed on the PLINE (Command) page.

Arrows inside drawing symbols: arrowheads, view direction and levels

There is one more family of arrows, and this one has no command of its own.

Dimension arrowheads. This is the most misunderstood case. Vietnamese construction drawings use an oblique tick at each end, not an arrow; arrows are a mechanical-drawing convention. The default ISO-25 style uses a solid arrow. Type D and Enter to open DIMSTYLE, click Modify, go to Symbols and Arrows, and set both Arrowheads fields to Architectural tick. Our article on construction drawing symbols covers the wider set of conventions.

View direction arrows on a section line. Two heavy strokes at the ends of the cut line, arrows pointing the way the viewer looks, and the same reference letter at both ends. Point them the wrong way and the section comes out reversed.

Level marks. A hollow triangle with its apex on the surface being annotated, and the figure written above it. Levels are given in metres to three decimal places, even when the model is drawn in millimetres. A slab at 3600 millimetres is annotated 3.600, not 3600.

Build all three once as attributed blocks and insert them afterwards. Change the convention later and you edit one place.

Common mistakes when drawing arrows in CAD

The arrow is microscopic, or fills the sheet. The scale factor on the Leader Structure tab is wrong. Set it to the denominator of the drawing scale.

Editing the text leaves the leader behind. A sign you used LINE plus TEXT instead of a Multileader. Delete it and redo it with MLEADER.

Notes stagger like a staircase. Run MLEADERALIGN over each area before plotting.

Dimensions end in arrows where a construction set wants ticks. Change it in DIMSTYLE, tab Symbols and Arrows, then update the style.

Door tags typed as text, so nothing can be scheduled. Switch the multileader style to block content.

An arrow drawn with PLINE disappears on the plot. Polyline width is geometric width, while plotted lineweight comes from the layer. Check the layer and the plot style table if it shows on screen but not on paper.

Frequently asked questions

What is the alias for MLEADER?

Type MLD and press Enter. The style dialog is MLS. The align command has no default alias, so MLEADERALIGN must be typed in full.

How do LEADER, QLEADER and MLEADER differ?

LEADER and QLEADER are the older commands. They still run, but their text and leader remain separate objects. MLEADER merges them into one object with its own style, and only multileaders can be aligned. New drawings should use MLEADER.

Why does my arrow keep its old shape after I pick a different style?

Changing the current style in the Multileader Style Manager only affects notes drawn afterwards. To restyle existing ones, select them and change the Multileader style field in the Properties palette.

How do I get several arrows pointing at one line of text?

Select the note, right-click, and choose Add Leader. Each pass adds one more leader to the same text.

Is it faster to draw an arrow in CAD with lisp?

For repetitive work, yes — especially when placing many notes with the same wording. But the style has to be right first, because a lisp routine calls the command; it does not redesign the style for you.

Related articles

• What is AutoCAD — a handbook for people working in construction
• Construction drawing symbols — the conventions, including arrowheads and level marks
• What advanced AutoCAD covers — ten job skills once the drawing commands are second nature
• How to read construction drawings — reading cut lines and view directions on a plan