You dimension a wall four metres long. The software draws two extension lines and a horizontal line, but the measurement is nowhere to be seen and neither are the arrowheads. Zoom right in and there is a faint speck in the middle.
That is not a fault. It is dimension styles in AutoCAD left at the wrong setting, and specifically one number called DIMSCALE. The opening figure is the same 1000-unit dimension drawn three times with only that number changed: at 1 it looks empty, at 100 it reads properly. Everything below refers to the AutoCAD 2027 release. For the whole subject of dimensioning, the Institute runs an AutoCAD course for construction.
Where to start the DIMSTYLE command
The table below follows the acad.cuix interface file of the 2027 release.
| Command | Aliases | Ribbon | Classic menu |
|---|---|---|---|
DIMSTYLE | D, DDIM, DIMSTY, DST | Home → Annotation → Dimension Style | Dimension → Dimension Style |
DIMOVERRIDE | DIMOVER, DOV | Annotate → Dimensions → Override | Dimension → Override |
This command has four aliases, unusually many, and most people know only D.
Typing D opens the Dimension Style Manager dialog. There is also a hyphenated version for the command line, which Measured and rarely see mentioned:
Current dimension style: Standard Annotative: No
Enter a dimension style option [ANnotative/Save/Restore/STatus/Variables/Apply/?] <Restore>:
The STatus option prints every dimension variable currently in force. That is handy on an unfamiliar drawing where you want to know what the previous person set, without opening the dialog and clicking through seven tabs.
Dimension styles in AutoCAD come down to one number
This is the measured core of the article, and the good news is that most of the work sits in a single variable.
Drawing the same 1000-unit dimension with the dimension line offset 300, changed DIMSCALE across three values, and measured the bounding box of the dimension object itself.
DIMSCALE | Bounding box height | Excess over 300 | DIMTXT × DIMSCALE |
|---|---|---|---|
| 1 | 300.18 | 0.18 | 0.18 |
| 20 | 303.60 | 3.60 | 3.60 |
| 100 | 318.00 | 18.00 | 18.00 |
The excess matches the text height multiplied by the factor exactly, at all three values, without a hundredth out of place.
So the DIMSCALE variable is nothing vague: it is a multiplier, and it multiplies every plotted size. Autodesk describes the matching dialog control on the Fit Tab page for the 2027 release: "sets a scale for all dimension style settings that specify size, distance, or spacing, including text and arrowhead sizes".
The base text height is DIMTXT = 0.18. On a construction drawing measured in millimetres, text 0.18 mm tall is invisible. That is precisely why the bottom dimension in the opening figure looks empty: the text and arrowheads are there, just smaller than the linework.
The practical rule: a drawing plotted at 1:100 wants DIMSCALE set to 100; at 1:50, set 50. Type DIMSCALE, enter the number, press Enter — no dialog needed.
The dialog and the Fit tab
Type D and the Dimension Style Manager opens. Click Modify to edit the style in use, or New to create one.
The editing dialog carries seven tabs, per Autodesk's documentation: Lines, Symbols and Arrows, Text, Fit, Primary Units, Alternate Units and Tolerances.
| Tab | What it controls |
|---|---|
| Lines | Dimension and extension lines: colour, linetype, extension beyond, offset from origin |
| Symbols and Arrows | Arrowhead type and size, centre marks |
| Text | Text style, height, placement relative to the line |
| Fit | The overall scale factor, and behaviour when space is tight |
| Primary Units | Units, decimal places, prefixes and suffixes |
| Alternate Units | A secondary unit shown in brackets |
| Tolerances | Tolerance display |
The one worth going to is the Fit tab, under Scale for Dimension Features, the box marked Use overall scale of. That is DIMSCALE wearing a dialog.
The rest of the Fit tab is about what happens when a dimension is too small for its own text. The options decide whether the text moves outside, the arrows move outside, or both, and on a crowded reinforcement drawing that choice is made dozens of times per sheet. Setting it once in the style beats dragging text by hand afterwards, which is what most people end up doing and what makes a drawing set look inconsistent.
A piece of practical advice: do not edit the Standard style. Create a new one named after the scale, IIC-100 for instance, and keep one style per scale. Receiving a drawing where Standard has been quietly altered is an everyday occurrence; a style with a meaningful name explains itself.
DIMSCALE and DIMLFAC are not the same thing
This confusion does the most damage, because it makes the number printed on the drawing wrong rather than merely ugly.
Two variables that sound alike do opposite jobs:
| Variable | What it changes | Default measured |
|---|---|---|
DIMSCALE | The size of the linework: text, arrows, spacing | 1.0 |
DIMLFAC | The measurement itself | 1.0 |
Set DIMSCALE to 100 and the text grows a hundredfold while the measurement still reads 4000. Set the DIMLFAC variable to 100 and the text stays tiny while the measurement becomes 400000.
Autodesk is explicit about the overall scale control: "this scale does not change dimension measurement values". Anyone looking at a drawing whose dimensions read several times too large should check DIMLFAC first, not DIMSCALE.
To adjust a single dimension without touching the style, use DIMOVERRIDE, aliased DOV. It overrides variables on exactly the objects you select. Dimensioning in general is covered in our article on dimensions in AutoCAD.
The variables worth knowing
Besides DIMSCALE, these are the ones construction drafters reach for, with the defaults measured on our machine:
| Variable | Default | Meaning |
|---|---|---|
DIMTXT | 0.18 | Text height before the factor is applied |
DIMASZ | 0.18 | Arrowhead size before the factor is applied |
DIMEXE | 0.18 | Extension line overshoot past the dimension line |
DIMEXO | 0.0625 | Gap between the object and the start of the extension line |
DIMANNO | 0 | Whether the style is annotative |
The first three are all multiplied by DIMSCALE, so setting that one variable carries all three with it. Editing them individually only matters when you want a different ratio between them, a smaller arrowhead against the text for instance.
DIMANNO marks a different route entirely: an annotative style scales itself to the viewport, so DIMSCALE never has to be set by hand. That suits drawings with several scales, but it needs everyone on the project working the same way, so it is a decision for the team rather than the individual. Choosing aliases for everyday commands is covered in our article on command aliases in AutoCAD.
Three things tutorials leave out
| What people assume | What the 2027 release actually does |
|---|---|
| A dimension with no text is a software fault | No. The text is there, sized DIMTXT × DIMSCALE |
DIMSCALE changes the measured value | No. It changes sizes only; DIMLFAC changes the value |
| Editing a style needs the dialog | -DIMSTYLE runs on the command line, with STatus to list everything |
Nine times in ten, a "broken" dimension needs nothing more than DIMSCALE set to the plotting scale. Only the tenth needs the dialog.
On a drawing arriving from another office, three commands are worth typing straight away: DIMSCALE to learn the factor in use, DIMLFAC to check whether the measurements are being multiplied, and -DIMSTYLE with STatus for the full picture. It takes under a minute and heads off most of the misunderstandings that follow.
The same three readings settle an argument that comes up on nearly every project. When one consultant's dimensions look twice the size of another's on the same sheet, the cause is almost always two different DIMSCALE values rather than anyone drawing anything wrongly, and the fix is a single number rather than a redraw.
One habit is worth forming on a multi-sheet set. Decide the plotting scale before dimensioning anything, and set DIMSCALE at the start. Fixing it afterwards works, but any dimension you nudged by hand where space was tight will be nudged out of place again, and each one has to be tidied individually.
Frequently asked questions
What is the alias for the dimension style dialog?
D. There are also DDIM, DIMSTY and DST, and all four work.
My dimension shows no number. Why?
DIMSCALE is still at 1 on a large-scale drawing. Type DIMSCALE and enter the plotting denominator, 100 for instance.
What value should DIMSCALE be?
The denominator of the plotting scale. A 1:50 sheet wants 50, a 1:100 sheet wants 100.
My measurements read several times too large. Where do I fix that?
Check DIMLFAC, not DIMSCALE. DIMLFAC multiplies the measured value itself.
How do I change one dimension without changing the style?
Use DIMOVERRIDE, aliased DOV, and select only the dimensions you want changed.
Should I edit the Standard style?
Better not. Create a new style named after the scale so whoever opens the drawing next can tell what it is for.