How LTSCALE works: AutoCAD defines linetype patterns in acad.lin (imperial) or acadiso.lin (metric) as sequences of dash lengths in drawing units. The LTSCALE variable multiplies all those lengths by a global factor. Set LTSCALE = your Scale Factor (SF) so the pattern reads correctly when plotted. For layouts, set PSLTSCALE = 1 (viewport-relative scaling) to avoid double-scaling. The preview below updates live as you move the slider.
Linetype Quick Reference
Linetype Name
Pattern Description
acad.lin Pattern
Common Use
LTSCALE Tip
✎ Custom Linetype Creator
Build your own .LIN file pattern from scratch — with live preview and one-click copy
How the builder works: Give your linetype a name and description, then add Dash, Gap, and Dot segments in order. The builder generates the exact syntax to paste into a .lin file, which you load into AutoCAD with the LINETYPE command. One period (one complete cycle of your pattern) repeats along the entire line.
📄 Linetype Identity
⚠ Name: letters, numbers, underscores, hyphens only — no spaces. Keep under 31 characters for compatibility.
■ Pattern Segments — one full cycle (period)
Pattern rules: Segments execute left-to-right, then repeat. Start with a Dash — AutoCAD's A-alignment always begins at a pen-down position. Alternate dashes and gaps for best results. A Dot is a zero-length dash (pen touches paper for one point). The period is the sum of all absolute values.
Period: 0.00 units
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Segments: 0
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Dashes: 0
Gaps: 0
Dots: 0
#
Type
Length (units)
.LIN Value
Move
Remove
units
✎ Text Element Parameters
Y= set to negative half of S= to center text on the line (e.g. S=0.1 → Y=−0.05).
X= shifts start along the line.
S= is multiplied by LTSCALE at display — at LTSCALE=48, S=0.1 renders as 4.8 drawing units tall.
Style must exist in the drawing (STANDARD always exists).
ⓘ Units are drawing units. At LTSCALE=48 (1/4"=1'-0"), a 0.5-unit dash = 24 model inches. Text S= is also multiplied by LTSCALE.
👁 Live Preview — pattern repeats across the line
48
📄 Generated .LIN File Code
Copy the two lines below and paste them into a .lin file (or directly into acad.lin). Each linetype in a .lin file is exactly two lines: a descriptor line starting with * and a pattern line starting with A,
; Add a name and at least one segment to generate code
📊 Segment Breakdown — plotted lengths at LTSCALE 48 (1/4"=1'-0")
.LIN file location: AutoCAD ships with two standard linetype definition files — acad.lin (imperial) and acadiso.lin (metric). Located in: C:\Users\[user]\AppData\Roaming\Autodesk\AutoCAD 2024\R24.3\enu\Support\. You can add custom linetypes directly to these files, or create your own company.lin file and load it alongside the standard one. A separate file is recommended — it won't be overwritten by AutoCAD updates.
📄 .LIN File Structure — Annotated
; Lines starting with semicolon are comments — ignored by AutoCAD; You can use comments to organize your .lin file by discipline; ─────────────── DESCRIPTOR LINE ───────────────*CENTER,Center ____ _ ____ _ ____ _│ │ └── Description (optional, shown in AutoCAD linetype list)│ └─────── Comma separates name from description└─────────────── Asterisk (*) marks the start of a new linetype; ─────────────── PATTERN LINE ───────────────────A, 1.25,-.25,.25,-.25│ │ │ │ └── Negative = gap (pen UP) 0.25 units│ │ │ └─────── Positive = dash (pen DOWN) 0.25 units (the short dash)│ │ └──────────── Negative = gap (pen UP) 0.25 units│ └────────────────── Positive = dash (pen DOWN) 1.25 units (the long dash)└───────────────────── A = aligned pattern (starts/ends on a dash at endpoints); Full period = 1.25 + 0.25 + 0.25 + 0.25 = 2.0 units; LTSCALE multiplies all values: at LTSCALE=48, long dash = 60" = 5'-0"
■ Pattern Element Types
■ Dash (Positive Number)
0.5
Pen is down — draws a visible line of the specified length in drawing units. Any positive non-zero value. The dash length before LTSCALE multiplication.
Pen is up — creates a visible space (gap) of the specified absolute length. Always written as a negative value. Required between every dash/dot pair.
Examples: -0.0625, -0.125, -0.25, -0.5
· Dot (Zero)
0
Pen touches paper for an infinitely short stroke — creates a dot. Must be followed by a gap. A dot is technically a zero-length dash, not a gap.
Always written as: 0 (followed by a negative gap value)
✎ Text Element
["GAS",STANDARD,S=.1,A=0,X=-0.05,Y=-0.05]
Embeds text characters in the linetype. S=text height (before LTSCALE), A=rotation angle, X=horizontal offset, Y=vertical offset from the line. Style must exist in drawing.
Common use: GAS, SS (sanitary sewer), ST (storm), CATV, TEL
◆ Shape Element
[BATTING,LTYPESHP.SHX,S=.2,A=0,X=0,Y=0]
Embeds a compiled shape (.SHX) from a shape library file. AutoCAD ships with LTYPESHP.SHX containing BATTING, BOX, CIRC1, TRACK1, ZIGZAG, and others. Requires the .SHX file on the support path.
Available shapes: BATTING, BOX, CIRC1, TRACK1, ZIGZAG
✎ A-Code Alignment
A, ...
The A at the start of every pattern line stands for aligned. AutoCAD adjusts the pattern so both endpoints of every line/arc start and end on a dash stroke — never in a gap. This is the only valid alignment code in AutoCAD.
Always required: A, (then your comma-separated elements)
💬 Text Linetype — Full Example
; Gas line with embedded "GAS" text*GAS_MAIN,Gas line __ GAS __ GAS __A,.5,-.2,["GAS",STANDARD,S=.1,A=0,X=-.05,Y=-.05],-.2; Breakdown:; .5 = 0.5 unit dash (pen down); -.2 = 0.2 unit gap before text; [text element] = "GAS" at 0.1 height, centered on line; -.2 = 0.2 unit gap after text; Note: X/Y offsets shift the text so it's centered vertically on the line; Y=-0.05 = half the text height (0.1 / 2 = 0.05) — centers it on the line
⚡ Complex Pattern Math
Rule of thumb for readable patterns: The period (sum of all segment absolute values) should be approximately 0.5–2.0 inches when plotted. At LTSCALE=48 (1/4"=1'-0"), a period of 1.0 drawing units = 48" plotted ÷ 1" on paper... wait, no. LTSCALE multiplies the pattern values: period 1.0 units × LTSCALE 48 = 48 drawing units = 4 feet at 1/4"=1'-0". That plots as 1 inch. To get a 0.5" plotted period at 1/4" scale: target period = 0.5" × 48 (LTSCALE) / 12 (in/ft) ... actually at 1/4"=1'-0" your scale factor is 48, meaning 1 inch on paper = 48 inches = 4'-0" in model. So pattern values in drawing inches: period = 0.5" plot × 48 SF = 24" = 2.0 units if you work in feet, or 24.0 units if you work in inches model space. Bottom line: design your base pattern in whatever units your drawing uses, then LTSCALE brings it to the correct plotted size automatically.
Desired plotted period
LTSCALE 48 (1/4"=1'-0")
LTSCALE 96 (1/8"=1'-0")
LTSCALE 20 (Metric 1:20)
LTSCALE 100 (1:100)
1/4" on paper
0.25" base → pattern: 0.25
0.25" base → pattern: 0.25
pattern: 0.25 mm
pattern: 0.25 mm
1/2" on paper
pattern: 0.5 (draws 2' in model)
pattern: 0.5 (draws 4' in model)
pattern: 0.5 mm
pattern: 0.5 mm
1" on paper
pattern: 1.0 (draws 4' in model)
pattern: 1.0 (draws 8' in model)
pattern: 1.0
pattern: 1.0
2" on paper
pattern: 2.0 (draws 8' in model)
pattern: 2.0
pattern: 2.0
pattern: 2.0
Base pattern values above assume LTSCALE=1 — AutoCAD multiplies them by LTSCALE at display time. So enter your "natural" values and let LTSCALE do the scaling.
Click "Load in Builder" to send an example into the Builder tab for editing. "Copy .LIN" copies the raw code to your clipboard — paste directly into a .lin file.
Two ways to load a custom linetype: (1) Add your lines to an existing .lin file, or (2) create a separate company.lin file and load it. Method 2 is safer — your customizations survive AutoCAD reinstalls and updates.
Method A — Add to Existing acad.lin File
Find your acad.lin file. Default location: C:\Users\[YourName]\AppData\Roaming\Autodesk\AutoCAD 2024\R24.3\enu\Support\acad.lin. Open File Explorer, paste this path (replacing [YourName] with your Windows username). You can also type LINETYPE in AutoCAD → Load → and see the current file path at the top of the Load dialog.
Back up the file first. Copy acad.lin to acad.lin.bak in the same folder. If you make a typo, you can restore it.
Open in Notepad or any plain-text editor. Right-click → Open With → Notepad. Do NOT use Word or WordPad — they add invisible formatting characters that break the .lin parser.
Scroll to the bottom and paste your two-line definition. Each linetype is exactly two lines — no blank lines between the * line and the A, line.
Save the file with File → Save (Ctrl+S). Keep it as a plain .txt / .lin — do not change encoding.
Load into AutoCAD. Type LINETYPE → click Load… → your new linetype should appear in the list. Select it and click OK. Then click Close. Apply to a layer via the Layer Properties Manager.
Method B — Create a Separate company.lin File (Recommended)
Create a new text file using Notepad. Save it as company.lin (make sure "Save as type" is "All Files" — not .txt). Save it to your Support folder: C:\Users\[YourName]\AppData\Roaming\Autodesk\AutoCAD 2024\R24.3\enu\Support\
Add a header comment at the top: ; Company Standard Linetypes — [Your Name] — [Date]. Then paste your linetype definitions below.
In AutoCAD: Type LINETYPE → Load → click the File… button in the Load dialog → navigate to and select your company.lin file → your custom linetypes appear in the list → select and load.
For templates: After loading, save your .dwt template file with the linetype already loaded. Anyone opening a drawing from that template gets your custom linetypes automatically — no manual loading required.
For network deployments: Save your .lin file to a shared network path, then add that path to AutoCAD's Support File Search Path via OPTIONS → Files → Support File Search Path. AutoCAD will find your .lin file automatically from any workstation.
Command-Line Loading (Advanced)
; Load a linetype via command line (scriptable / LISP-callable)-LINETYPE; AutoCAD prompts: ?/Create/Load/Set: L← type L for Load; Linetype(s) to load: MY_GAS_LINE← exact linetype name from .lin file; File to search: company.lin← .lin filename (on support path) or full path; Apply to current layer via LAYER command:-LAYERL← Linetype optionMY_GAS_LINE← linetype nameU-GAS← layer name to apply it to
Important System Variables
Variable
Default
What It Does
LTSCALE
1.0
Global linetype scale — multiply all pattern lengths. Set to your Scale Factor (e.g. 48 for 1/4"=1'-0"). Affects all linetypes in all viewports.
PSLTSCALE
1
Paper Space Linetype Scale. When set to 1, viewport display scale controls linetype appearance. Set to 0 to use LTSCALE in all viewports (old behavior).
CELTSCALE
1.0
Current Entity Linetype Scale — object-level multiplier applied on top of LTSCALE. Set to 0.5 to make one object's pattern half the global size.
MSLTSCALE
1
Model Space Linetype Scale. When set to 1, uses annotation scale. Set to 0 for legacy behavior. (AutoCAD 2008+)
LTSCALELOCK
0
When 1, locks LTSCALE so users can't accidentally change it. Useful in template files.
ACADLINTYPEMATCH
1
When 1, AutoCAD tries to match linetype names when importing from other drawings. Set to 0 if you're getting unexpected linetype substitutions.
The triple-scale formula: Plotted linetype pattern length = base value × CELTSCALE × LTSCALE. In a Layout viewport with PSLTSCALE=1: plotted length = base value × CELTSCALE × viewport scale factor.
Troubleshooting Custom Linetypes
Problem
Cause
Fix
Line shows as Continuous
LTSCALE too high or period too small — pattern smaller than 1 pixel
Lower LTSCALE or increase base pattern values
"Invalid linetype definition" error
Syntax error in .lin file — missing comma, wrong sign, blank line between * and A,
Open .lin in Notepad, check for missing commas, no spaces in name, no blank line
Pattern doesn't start at line endpoint
Normal — use A-alignment. For very short lines, the pattern may not complete a full period
Use CELTSCALE to reduce scale so period fits within line length
Text in linetype too large/small
S= parameter needs adjusting relative to LTSCALE
S= is multiplied by LTSCALE. S=0.1 at LTSCALE=48 → text is 4.8 units tall
Shape not found / missing
LTYPESHP.SHX not on support path
Check Options → Support File Search Path includes AutoCAD's support folder
Linetype disappears after PURGE
Linetype not used by any object or layer — PURGE removes unused linetypes
Apply to at least one layer before purging, or use layer named _LINETYPES and set non-purgeable
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