You assign a hidden linetype to a line and it draws as one unbroken stroke. You assign it again, and nothing changes. The LTS command in AutoCAD fixes that in one line — but set the wrong number and the dashes still will not appear.
This article shows how to pick the number from your plot scale, and the three other variables that also have a say. For the whole discipline of setting up layers and linetypes for a drawing set, the Institute runs an AutoCAD course for construction.
LTS is the alias for LTSCALE
The alias file acad.pgp on the 2027 release holds exactly one line for it:
```
LTS, *LTSCALE
```
So typing LTS and pressing Enter opens the ltscale variable directly and asks for a new value. There is no separate command called LTS; it is only a shorthand. Editing aliases is covered in our article on command aliases in AutoCAD.
On a fresh drawing the four related variables start at:
| Variable | Default | What it does |
|---|---|---|
LTSCALE | 1 | A global multiplier for every linetype in the drawing |
CELTSCALE | 1 | A multiplier written into the next object drawn |
PSLTSCALE | 1 | How linetypes are measured inside layout viewports |
MSLTSCALE | 1 | Linetypes follow the annotation scale in model space |
Dashed lines not showing: 52 cycles read as one stroke
The cause is nearly always a division.
Every linetype has a cycle: one dash plus one gap. Read straight out of acadiso.lin on the 2027 release:
| Linetype | Definition | Cycle |
|---|---|---|
HIDDEN | 6.35, −3.175 | 9.5 |
DASHED | 12.7, −6.35 | 19.05 |
DASHDOT | 12.7, −6.35, 0, −6.35 | 25.4 |
CENTER | 31.75, −6.35, 6.35, −6.35 | 50.8 |
A 1000 mm line set to DASHED at scale 1 holds 1000 ÷ 19.05 ≈ 52 cycles. Fifty-two dashes along a span the width of a room read as a solid stroke on screen and on paper alike.
Raise the scale to 30 and the cycle becomes 571.5, so the same line holds 1.7 cycles and the dashes are plain. That is the whole story behind linetype scale in autocad.
Setting linetype scale from the plot scale
The quick rule that rarely misses: set it to the inverse of the plot scale, exactly as with dimension text.
| Plotted at | LTSCALE | DASHED cycle on the model |
|---|---|---|
| 1:100 | 100 | 1,905 mm |
| 1:50 | 50 | 952 mm |
| 1:20 | 20 | 381 mm |
That makes each cycle print at roughly 19 mm, which is on the loose side for fine hidden detail. Plenty of offices halve it and use 50 for a 1:100 sheet. This is a house convention worth fixing in your template rather than a number with one right answer.
Typing the value regenerates the drawing immediately. If it does not, type REGEN.
The celtscale variable: a scale for one object
LTSCALE is global: changing it changes every linetype in the drawing. When only a few lines should run looser or tighter than the rest, that is what CELTSCALE is for.
The point to grasp: CELTSCALE only acts at the moment of drawing. Its value is written into the object as its own Linetype scale property, and stays there.
| What you do | The object's property |
|---|---|
Set CELTSCALE to 1.0 and draw | Linetype scale = 1.000 |
Set CELTSCALE to 2.5 and draw | Linetype scale = 2.500 |
Then set LTSCALE to 30 | Both stay at 1.000 and 2.500 |
The effective scale of any line is the product of two numbers: LTSCALE × the object's Linetype scale. A drawing at LTSCALE 30 with a line carrying 2.5 runs that line at 75.
To fix a line already drawn, select it, press Ctrl+1 and edit Linetype scale. Select a whole group to change many at once.
The psltscale variable: dashes inside layout viewports
This is where plotting from layouts gets confusing, because every viewport has its own zoom.
Autodesk's page on the PSLTSCALE variable describes it briefly: "Controls the linetype scaling of objects displayed in paper space viewports". It takes two values:
| Value | Autodesk's wording |
|---|---|
| 0 | "No special linetype scaling. Linetype dash lengths are based on the drawing units of the space (model or paper) in which the objects were created." |
| 1 | "Viewport scaling governs linetype scaling. If TILEMODE is set to 0, dash lengths are based on paper space drawing units, even for objects in model space." |
Left at 1, dashes print identically in every viewport whether it is scaled 1:50 or 1:200. That is what you want almost always, and it also means LTSCALE should sit near 1 rather than near 100.
One caveat Autodesk states plainly: "When you change PSLTSCALE or use a command such as ZOOM with PSLTSCALE set to 1, objects in viewports are not automatically regenerated with the new linetype scale. Use the REGEN or REGENALL command to update the linetype scales in each viewport." If nothing moves after the change, run REGENALL before concluding anything.
Still solid: four places to check
When the scale is up and the line is still unbroken, the effective scale is being held back in one of four places. Work through them; each takes seconds.
One — does the object carry a linetype? Select it, press Ctrl+1, look at Linetype. If it reads ByLayer, the layer decides, not the object.
Two — what linetype does its layer carry? Type LA, find the layer, check the Linetype column. A layer left on Continuous draws every ByLayer object solid no matter what scale you set.
Three — the object's own scale. Still in Properties, check Linetype scale. A line carrying 0.01 runs at an effective scale of 1 even with LTSCALE at 100.
Four — model space or layout. Inside a layout viewport with PSLTSCALE at 1, dash lengths are measured in paper units rather than following LTSCALE as they would in model space.
The four multiply together, so one wrong value spoils the result. That is why typing a very large number and seeing nothing change is so common: the large number is being multiplied by a very small one somewhere else.
Put it in the template once
All four variables — LTSCALE, CELTSCALE, PSLTSCALE, MSLTSCALE — are stored in the drawing, not on the machine. Set them here and a new drawing starts back at the defaults.
The way to stop repeating the work: open your office template, set the four to your house convention, preload the linetypes you use with LINETYPE, and save it as a .dwt. Every drawing started from it arrives complete.
One step further makes it invisible: assign the linetype to each layer in the template. A HIDDEN layer carries the hidden linetype, a CENTRE layer the centre line. Draughtsmen pick a layer and never think about linetypes at all.
There is a practical reason to standardise rather than leave it to each person. Because the value lives in the file, a drawing you receive opens with whatever the sender used, not with your office setting. Open a consultant's file whose LTSCALE is 1 while yours is 50 and every hidden line looks solid — which reads as a drafting error when it is only a number. Before anyone raises a comment on a received drawing, type LTS and see what it reports.
The reverse matters as much. A drawing you issue carries your number with it, so the value is part of what you are handing over. Fixing it in the template means every sheet the office issues behaves the same way, and a reviewer opening any of them sees what you plotted. Agreeing the convention across a project team costs one email.
Three things often repeated that are not true
| Often repeated | What was measured |
|---|---|
| Assign a linetype and the dashes appear | At scale 1 a 1000 mm line holds 52 cycles and reads as solid |
Changing LTSCALE puts every line on one scale | Any object with its own Linetype scale still multiplies by it |
CELTSCALE fixes lines already drawn | It acts only at draw time; existing lines are edited in Properties |
Frequently asked questions
How do I use the LTS command in AutoCAD?
Type LTS, press Enter, and AutoCAD asks for a new linetype scale factor. It is the acad.pgp alias for LTSCALE.
The dashes still do not show even at a high scale.
Check three things: whether the object carries a linetype at all or only ByLayer, what linetype its layer carries, and whether the object has a tiny Linetype scale of its own.
Should I set LTSCALE or edit each object?
Set LTSCALE once for the drawing. Edit individual objects only for a specific reason, since that number travels with the object and the next person will struggle to find it.
What should I use when plotting from a layout?
Leave PSLTSCALE at 1 and keep LTSCALE near 1. Dashes then print the same in every viewport.
Where can I see a linetype's cycle length?
Open acadiso.lin in the Support folder with Notepad. The numeric line under each name gives the dash and gap lengths.
Can I write my own linetypes?
Yes. Writing a .lin file, and the Institute's own set, are covered in our article on an AutoCAD linetype library.