How to Create Custom Linetype in AutoCAD Quickly

To create a custom linetype in AutoCAD, you write a .lin file defining the pattern using text codes and dashes, then load it into AutoCAD using the LINETYPE command. The file specifies line segments, gaps, and optional text or shapes to form the custom pattern.

Syntax

A custom linetype is defined in a .lin file with this structure:

• Linetype name: Starts with an asterisk (*) followed by the name.
• Description: A quoted string describing the linetype.
• Pattern definition: A series of numbers and text codes defining line segments and gaps.

Each pattern line uses numbers for dash lengths (positive for line, negative for gap) and optional text enclosed in <> for embedded shapes or text.

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*CustomDash "Custom dashed line" 0.5,-0.25,0.1,-0.25

Example

This example creates a custom linetype with alternating dashes and gaps:

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*MyDash "Dash and gap pattern" 0.5,-0.25,0.1,-0.25

Output

A line pattern with 0.5 units dash, 0.25 units gap, 0.1 units dash, 0.25 units gap repeating.

Common Pitfalls

• Forgetting the asterisk (*) before the linetype name causes AutoCAD to reject the pattern.
• Incorrect dash and gap lengths can make the pattern invisible or look wrong.
• Not loading the .lin file into AutoCAD before use.
• Using unsupported characters or missing quotes in the description line.

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Wrong:
*CustomDash "No asterisk" 0.5,-0.25

Right:
*CustomDash "Proper name" 0.5,-0.25

Quick Reference

Element	Description
*LinetypeName	Starts the linetype definition with an asterisk
"Description"	Quoted text describing the linetype
Positive number	Length of a dash (line segment)
Negative number	Length of a gap (space)
	Optional text or shape embedded in the pattern
Comma-separated values	Sequence of dashes, gaps, and text

Key Takeaways

Always start the linetype name with an asterisk (*) in the .lin file.

Define dash and gap lengths carefully to make the pattern visible and clear.

Load your custom .lin file into AutoCAD using the LINETYPE command before use.

Use quotes around the description and follow the syntax strictly to avoid errors.