Roof pitches, the angle between two grid lines, a bend in a pipe run, the sweep of an arc: every drawing has a few angles to dimension. An angular dimension in AutoCAD uses DIMANGULAR, and it behaves differently from other dimension commands: for the same pair of lines, the value depends on where you place the dimension arc.
This article tries DIMANGULAR on two lines, an arc, a circle and three points, and covers angle decimals and units, in AutoCAD 2027 with the acadiso.dwt template. Every value is read back from the dimension object. Drawing a given angle is covered in drawing angles in AutoCAD. For dimensioning taught properly, the Institute runs an AutoCAD course for construction.
The DIMANGULAR command and where to find it
| Route | Where |
|---|---|
Type DIMANGULAR or alias DAN | Command line |
| Ribbon | Annotate tab → Dimensions panel → Linear drop-down → Angular |
| Menu | Dimension → Angular |
| Toolbar | Dimension → Angular |
Locations and aliases come from the 2027 acad.cuix and acad.pgp files. The Autodesk documentation on DIMANGULAR describes the dimangular command as measuring the angle between two lines or three points. Its first prompt in 2027 is:
Select arc, circle, line, or <specify vertex>:That prompt leads four ways, depending on what you pick:
| You pick | Next prompt | Angle measured |
|---|---|---|
| A line | Select second line: | Between the two lines |
| An arc | (none) | The arc's included angle |
| A circle | Specify second angle endpoint: | From the picked point to the second, seen from the centre |
| Enter | Specify angle vertex:, then two endpoints | At the vertex, through three points |
Last comes the placement prompt: Specify dimension arc line location or [Mtext/Text/Angle/Quadrant]:. The ° sign is added for you and stored in the dimension text as \U+00B0; there is no need to type %%d.
Dimension an angle in AutoCAD between two lines
Two lines start from one point, one horizontal and one at 60°. Select both, then place the arc on four different sides:
| Arc placed | Value |
|---|---|
| Inside the angle between the lines | 60° |
| Above left | 120° |
| In the vertically opposite sector | 60° |
| Below right | 120° |
AutoCAD treats the lines as infinite, which makes four sectors around the intersection: two opposite 60° sectors and two opposite 120° sectors. Where you place the arc decides which one is dimensioned. With two lines the value never exceeds 180°: there is no way to get 240° or 300°.
The two values always add up to 180°. If a drawing shows 120° where the eye sees an acute angle, the arc was almost certainly placed in the supplementary sector. It happens most when the lines do not actually meet on the drawing, only where they would if extended, so the person placing the arc cannot see the intersection. Right after placement the command line prints the value, e.g. Dimension text = 120; a glance at it after every angle catches the wrong sector before it is buried among other dimensions.
To be sure of the angle while placing the arc somewhere tidier, use the Quadrant option. Type Q, click inside the angle you want, then place the arc. A 37.5° angle locked with Quadrant and then placed on the opposite side still measures 37.5° (displayed as 38° because of rounding, see below).
Arcs and circles
Pick an arc and AutoCAD dimensions its included angle at once. An arc swept from 0° to 135° gets 135° with no further points.
A circle works differently: the point where you click becomes the first end of the angle, and AutoCAD asks Specify second angle endpoint:. Click at 0° to select, then at 90°, and it shows 90°, measured from the centre. This is handy for the spacing of bolt holes on a round flange: pick the circle at one hole and click the next hole to get the angular pitch between them.
Three points: the only way past 180°
Press Enter at the first prompt; AutoCAD asks for the vertex (Specify angle vertex:) and two endpoints. With the vertex at a corner, one end to the right and one above:
| Arc placed | Value |
|---|---|
| Inside the angle | 90° |
| Outside, opposite | 270° |
Unlike two lines, the three-point form can exceed 180°. Use it for the outside angle of a wall corner or the swing of a gate.
One caution: typing the three points without snapping to geometry prints Non-associative dimension created., so the dimension is attached to nothing and will not follow edits. The same happens in aligned dimensions; the cure is snapped points.
DIMADEC: angle decimals
A 37.5° angle dimensioned with the default acadiso.dwt style shows 38°. The stored measurement is still 37.5; only the displayed text is rounded. The DIMADEC variable sets the decimals of angles, and DIMAUNIT sets the angle unit:
| DIMAUNIT | DIMADEC | Displayed |
|---|---|---|
| 0 (decimal degrees) | 0 | 38° |
| 0 | 1 | 37,5° |
| 0 | 2 | 37,50° |
| 1 (degrees/minutes/seconds) | 0 | 38° |
| 1 | 2 | 37°30' |
In every row of that table the stored measurement read back from the object is exactly 37.5; the variables change only what is printed. A LISP routine or a data extraction that reads the measurement therefore gets 37.5 even when the sheet shows 38°, so the printed value and the extracted value can disagree unless DIMADEC is set before dimensioning.
Two lessons. A drawing with an odd angle such as a 37.5° roof pitch needs a higher DIMADEC, or the builder reads 38°. And for surveying-style degrees and minutes, set DIMAUNIT to 1 and DIMADEC to 2. The acadiso.dwt template uses a decimal comma, hence "37,5". Dimension styles in general are covered in dimension styles in AutoCAD.
Summary: what each method gives
| Method | Example | Value | Object type created |
|---|---|---|---|
| Two lines, arc inside the angle | Lines 60° apart | 60° | 2LineAngularDimension |
| Two lines, arc in the other sector | Same lines | 120° | 2LineAngularDimension |
| An arc | Arc from 0° to 135° | 135° | 3PointAngularDimension |
| A circle, two points | Points at 0° and 90° | 90° | 3PointAngularDimension |
| Three points, arc inside | Right-angle corner | 90° | 3PointAngularDimension |
| Three points, arc outside | Same corner | 270° | 3PointAngularDimension |
The last column fits the behaviour above: AutoCAD stores a two-line dimension as a pair of lines, and everything else as a vertex with two points.
Every value in this table is stored exactly; what you see on paper also depends on DIMADEC, as shown above.
A worked order for an angular dimension in AutoCAD on a real plan
Putting the results together, here is a safe order for a plan with skewed grid lines and a 37.5° roof pitch:
- Before dimensioning, check
DIMADEC. If the drawing has odd angles, set it to at least 1 so that 37.5° is not rounded to 38°. - Angle between two grid lines: type
DAN, pick both lines, and drag the arc into the sector you mean. Check theDimension text =line: if it shows the supplementary angle, undo and place the arc on the other side. - If the arc has to sit elsewhere for clarity, type
Q, click inside the sector you want first, then place the arc. - Outside angle of a wall corner, over 180°: press Enter at the first prompt, pick the vertex and two endpoints with object snaps, then place the arc outside.
- Included angle of a curved wall: just pick the arc.
- Watch the command line. If it says
Non-associative dimension created., typeUand repeat with snapped points.
Following this order, each angle gets the right sector, the right decimals, and follows the geometry when the drawing is revised.
Three things often repeated that are not true
| Often repeated | What holds on the 2027 release |
|---|---|
| The angle between two lines is always the acute one | It is 60° or 120° depending on where the arc goes |
| For 270°, pick two lines and place the arc outside | Two lines never exceed 180°; use the three-point form |
| Angular dimensions show the exact value | By default they round to whole degrees: 37.5° shows 38° |
Frequently asked questions
Which command dimensions an angle in AutoCAD?
DIMANGULAR, alias DAN. Pick two lines, an arc, a circle, or press Enter for three points.
Why do I get 120° when I need 60°?
The arc was placed in the 120° sector. Drag it into the 60° sector, or lock the sector with Quadrant.
How do I dimension an angle larger than 180°?
Press Enter at the first prompt, pick the vertex and two endpoints, and place the arc outside: a right angle becomes 270°.
Why does 37.5° show as 38°?
DIMADEC is 0, so angles round to whole degrees. Set DIMADEC to 1.
How do I show degrees and minutes?
Set DIMAUNIT to 1 and DIMADEC to 2: 37.5° shows as 37°30'.
Do I need to type the degree sign?
No. AutoCAD adds the ° after the value automatically, in every angular dimension.