What Is a CAD Linetype and How Does It Work?

A CAD linetype is a repeating visual pattern applied to drawing geometry such as a line, polyline, arc or circle. Instead of displaying every object as a continuous line, CAD software can represent it with dashes, gaps, dots, text or symbols.

Linetypes help architects, engineers, designers and CAD technicians communicate technical information clearly. They can identify hidden edges, centerlines, property boundaries, utilities, construction limits and many other elements without adding a separate note beside every object.

A linetype changes the visual appearance of an object. The underlying geometry normally remains continuous and can still be selected, measured and edited as a single object.

What Is a CAD Linetype?

Simple CAD Linetype Definition

A linetype is a predefined sequence of visible and invisible elements repeated along the length of a CAD object.

A pattern may contain:

  • Visible line segments
  • Blank spaces
  • Dots
  • Embedded text
  • Custom shapes

A basic dashed pattern can be represented conceptually as:

Dash – Gap – Dash – Gap

A centerline may use a different sequence:

Long dash – Gap – Short dash – Gap

CAD software reads the pattern definition, applies the appropriate scale and repeats the sequence along the selected object.

Linetypes can normally be applied directly to objects such as:

  • Lines
  • Polylines
  • Arcs
  • Circles
  • Splines
  • Ellipses
  • Dimensions
  • Leaders
  • Objects inside blocks
  • Objects contained in external references

Some object types require special treatment.

Multilines, created with the MLINE command, do not use the standard object linetype property in the same way as ordinary lines. The linetype of each multiline element is defined inside its multiline style, managed with MLSTYLE.

Hatches use hatch patterns defined in .PAT files rather than standard linetype patterns defined in .LIN files. Their internal appearance is primarily controlled through the hatch pattern, scale and angle.

Linetype vs. Line Geometry

A line is a geometric object. It has a start point, an endpoint, a direction and a measurable length.

A linetype is a display property applied to that geometry.

For example, suppose a 1,000-millimeter line is assigned a dashed linetype. The object remains one continuous line measuring 1,000 millimeters. CAD software only displays it as a sequence of visible dashes and blank spaces.

The object can still be:

  • Selected as one object
  • Moved
  • Copied
  • Offset
  • Trimmed
  • Extended
  • Measured
  • Assigned to another layer

The spaces visible in the pattern are therefore not real geometric breaks.

This distinction is important because users sometimes create dashed lines manually from multiple short segments. That method produces unnecessary geometry and makes drawings harder to edit. In most cases, a single object with the correct linetype is the better solution.

Why Linetypes Are Important in Technical Drawings

Technical drawings must communicate more than dimensions and shape. They must also distinguish between different types of information.

For example:

  • A continuous line may represent a visible wall or mechanical edge.
  • A hidden line may represent an element behind another surface.
  • A centerline may identify the axis of a hole.
  • A phantom line may show an alternate position.
  • A property line may define a site boundary.
  • A utility linetype may identify a gas, water or electrical network.

Consistent linetype use improves:

  • Drawing readability
  • Technical communication
  • Coordination between disciplines
  • Compliance with CAD standards
  • Quality control
  • Plotting consistency

When linetypes are used correctly, the reader can often understand the function of an object before reading any annotation.

How Does a CAD Linetype Work?

The Repeating Linetype Pattern

Most CAD linetypes are based on a repeating sequence of numerical pattern elements.

In a simple AutoCAD linetype definition:

  • A positive value represents a visible line segment.
  • A negative value represents a blank space.
  • A zero value represents a dot.

For example:

0.50, -0.25

This pattern means:

  • Draw a visible segment measuring 0.50 drawing units.
  • Leave a blank space measuring 0.25 drawing units.
  • Repeat the sequence.

A more detailed pattern may look like:

1.00, -0.25, 0.25, -0.25

This produces:

  • One long dash
  • One blank space
  • One short dash
  • Another blank space
  • Repetition of the full sequence

The final visible size of the pattern depends on more than these numerical values. It can also be affected by:

  • Drawing units
  • Global linetype scale
  • Object linetype scale
  • Annotation scale
  • Viewport scale
  • Model Space and Paper Space settings

How CAD Applies the Pattern

When CAD software displays a linetype, it follows a process similar to this:

  1. It reads the object geometry.
  2. It identifies the assigned linetype.
  3. It calculates the active linetype scale.
  4. It repeats the pattern along the object.
  5. It displays or plots the result.

For a straight line, the pattern is repeated from one endpoint to the other.

For an arc, circle or spline, the pattern follows the actual curved path.

For a polyline, the behavior may depend on whether the pattern restarts at each vertex or continues across the complete object.

What Happens at Corners and Endpoints?

A linetype pattern does not always fit perfectly into the length of an object.

Near an endpoint, CAD software may:

  • Display a partial pattern
  • Shorten a visible segment
  • Adjust the last gap
  • Display only one dash
  • Make the object appear continuous

Short objects are especially likely to display incomplete patterns.

Polyline vertices introduce another issue. The pattern may restart at every vertex or continue through the corners as one uninterrupted sequence.

This behavior is controlled by the Linetype Generation property and the PLINEGEN system variable.

Linetype Generation Across Polyline Vertices

The PLINEGEN system variable controls how linetype patterns are generated when new 2D polylines are created.

  • PLINEGEN = 0: The pattern starts and ends with a dash at each polyline vertex.
  • PLINEGEN = 1: The pattern continues through the vertices as one continuous sequence.

Changing PLINEGEN primarily affects newly created polylines. Existing polylines can be modified through their Linetype Generation property in the Properties palette.

Continuous generation is often preferable for:

  • Property boundaries
  • Utility networks
  • Road alignments
  • Long architectural outlines
  • Site geometry

However, the best setting depends on the drawing standard and the type of object.

The Main Components of a CAD Linetype

Dashes and Visible Segments

Dashes are the visible portions of a linetype pattern.

They can have equal or different lengths.

Examples include:

  • Equal short dashes for hidden lines
  • Alternating long and short dashes for centerlines
  • Long dashes for boundaries
  • Mixed dash lengths for phantom lines

Dash length is an important part of the visual identity of a linetype.

Gaps and Blank Spaces

Gaps are the invisible portions placed between visible segments.

Without gaps, the line would appear continuous.

Gap size affects readability:

  • Gaps that are too small may disappear on screen or in print.
  • Gaps that are too large may make the pattern difficult to follow.
  • Large gaps may produce poor results around corners.
  • Small objects may not contain enough length to display a complete gap.

Dots

Dots are normally created with a zero-length pattern element.

They may be used alone or combined with dashes in patterns such as:

  • Dotted lines
  • Dash-dot lines
  • Centerlines
  • Survey lines
  • Grid lines

The printed appearance of a dot may also be influenced by lineweight and output resolution.

Embedded Text

A complex linetype can include repeated text.

Common examples include:

  • GAS
  • WATER
  • ELEC
  • FENCE
  • SANITARY
  • STORM
  • HOT WATER
  • PROPERTY LINE

The text is inserted directly into the repeating pattern.

A utility line may therefore appear as:

— GAS — GAS — GAS —

Embedded text references an AutoCAD text style. That text style uses a font, usually a .SHX font or a TrueType .TTF font.

If the original font is missing, AutoCAD may use a substitute font. This can change:

  • Text width
  • Text height
  • Alignment
  • Spacing
  • General pattern appearance

For reliable results, the required font and text style should be included in the project standards.

Embedded Shapes and Symbols

Embedded shapes are different from embedded text.

A symbol-based linetype references a named shape stored inside a compiled SHX shape file.

Examples include:

  • Arrows
  • Circles
  • Squares
  • Fence posts
  • Railway ties
  • Zigzag symbols
  • Flow indicators
  • Batting symbols

If the required shape file or shape definition is missing, the symbol may disappear or the linetype may not display correctly.

This distinction is important:

  • Embedded text depends on a text style and font.
  • Embedded shapes depend directly on a compiled SHX shape file.

Common Types of CAD Linetypes

Continuous Linetype

The Continuous linetype displays an unbroken line.

It is commonly used for:

  • Visible object outlines
  • Walls
  • Structural elements
  • Mechanical profiles
  • General drawing geometry
  • Dimensions
  • Leaders

It is usually the default linetype in a new drawing.

Dashed Linetype

A dashed linetype contains repeated visible segments separated by spaces.

It may be used for:

  • Secondary geometry
  • Existing conditions
  • Demolition work
  • Objects above or below a reference plane
  • Hidden components
  • Reference geometry

The meaning should always follow the drawing standard used for the project.

Hidden Linetype

A hidden linetype represents an edge or object that is not directly visible in the current view.

In mechanical drawings, it may show:

  • Internal holes
  • Recesses
  • Edges behind a surface
  • Concealed features

In architectural drawings, it may show:

  • Overhead cabinets
  • Beams above the plan cut
  • Foundations below floor level
  • Concealed equipment
  • Elements behind walls

Hidden patterns usually contain short, evenly spaced dashes.

Center Linetype

A center linetype commonly alternates long and short segments.

It is used for:

  • Hole centers
  • Axes
  • Symmetry lines
  • Circular centers
  • Mechanical shafts
  • Rotational paths

Centerlines are essential in engineering drawings because they define alignment and geometric relationships.

Phantom Linetype

A phantom linetype often combines one long dash with two shorter dashes.

It can represent:

  • Alternate positions
  • Moving components
  • Repeated details
  • Adjacent structures
  • Future work
  • Paths of motion

Its exact meaning depends on the drafting standard.

Border and Property Linetypes

Boundary-related linetypes are common in:

  • Civil engineering
  • Surveying
  • Site planning
  • Land development
  • Legal property drawings

They may identify:

  • Property boundaries
  • Easements
  • Rights of way
  • Municipal limits
  • Parcel divisions
  • Construction limits

Utility Linetypes

Utility linetypes distinguish different services in civil, architectural and MEP drawings.

They may identify:

  • Gas lines
  • Water lines
  • Stormwater networks
  • Sanitary sewer lines
  • Electrical cables
  • Communication networks
  • Fire protection systems
  • Irrigation lines
  • Fiber-optic cables

These patterns often use embedded text or symbols to remain recognizable when several services are close together.

Simple vs. Complex CAD Linetypes

What Is a Simple Linetype?

A simple linetype contains only:

  • Dashes
  • Gaps
  • Dots

It does not include embedded text or custom symbols.

Simple linetypes are generally:

  • Lightweight
  • Reliable
  • Easy to edit
  • Widely compatible
  • Easy to distribute

Common examples include:

  • Dashed
  • Hidden
  • Center
  • Phantom
  • Dot
  • Dash-dot
  • Border

Because they have few external dependencies, simple linetypes usually transfer well between drawings and CAD platforms.

What Is a Complex Linetype?

A complex linetype includes text or custom shapes in addition to ordinary dashes and spaces.

It may depend on:

  • Text styles
  • SHX fonts
  • TrueType fonts
  • Compiled SHX shape files
  • Rotation values
  • Text offsets
  • Shape offsets
  • Compatible CAD software

Complex patterns are useful when a line must identify a specific service, material or function.

Simple vs. Complex Linetypes Comparison

Feature Simple Linetype Complex Linetype
Dashes and gaps Yes Yes
Dots Yes Yes
Embedded text No Yes
Embedded shapes No Yes
External dependencies Rare Possible
File portability Usually high May require support files
Editing complexity Low Moderate to high
Typical use Hidden, center and dashed lines Utilities, fences and specialized symbols

Simple linetypes are normally preferable when compatibility and reliability are the main priorities.

Complex linetypes are more appropriate when the pattern must communicate more detailed technical information.

Where Are CAD Linetypes Stored?

AutoCAD LIN Files

AutoCAD and many compatible CAD programs store linetype definitions in files with the .LIN extension.

A LIN file is a plain-text file. It can be opened and edited with a standard text editor.

A LIN file may contain:

  • Linetype names
  • Descriptions
  • Dash values
  • Gap values
  • Dot values
  • Text references
  • Shape references
  • Rotation settings
  • Scale factors
  • X and Y offsets

A simplified definition begins with a name and description, followed by the numerical pattern instructions.

Because LIN files are text-based, users can create and modify custom linetypes without developing a compiled plugin.

Standard Linetype Files

A standard AutoCAD installation commonly provides:

  • acad.lin for imperial linetype definitions
  • acadiso.lin for metric or ISO linetype definitions

AutoCAD LT commonly uses corresponding files such as:

  • acadlt.lin
  • acadltiso.lin

The pattern names may be similar, but their numerical dimensions are designed for different unit systems.

Loading an imperial definition into a metric drawing can produce a pattern that appears too small or too dense. Loading a metric definition into an imperial drawing can produce a pattern that appears too large.

For this reason, the linetype library should match the drawing’s unit convention.

The MEASUREMENT System Variable

The MEASUREMENT system variable indicates whether the drawing uses imperial or metric support-file conventions.

  • MEASUREMENT = 0: Imperial conventions
  • MEASUREMENT = 1: Metric conventions

In a standard AutoCAD setup, this setting influences whether imperial or ISO support files are used by default.

However, MEASUREMENT does not automatically load every linetype definition into the drawing. Individual linetypes must still be loaded when required.

Linetypes Stored Inside DWG Files

When a linetype is loaded into a drawing, its definition is normally stored inside the DWG file.

This means a simple linetype can usually continue to display even when the original .LIN file is no longer available.

Complex linetypes may still require external support files such as:

  • SHX fonts
  • SHX shape files
  • TrueType fonts

If a required support file is missing, the pattern may not display as intended.

Unused linetype definitions can be removed with the PURGE command, provided they are not referenced by a layer, object, block or another drawing definition.

How Linetypes Are Assigned in CAD

Linetype Assigned ByLayer

When an object is assigned the value ByLayer, it inherits the linetype of its layer.

This is the recommended method for most professional drawings.

For example:

  • A-WALL may use Continuous.
  • A-OVERHEAD may use Hidden.
  • M-CENTER may use Center.
  • C-PROP may use a property-line pattern.

Using ByLayer provides:

  • Consistent standards
  • Faster editing
  • Easier quality control
  • Better layer management
  • Fewer object-level overrides

Changing the layer linetype updates all objects that inherit their properties from that layer.

Linetype Assigned ByBlock

The ByBlock setting is mainly used for objects inside reusable blocks.

An object set to ByBlock may adopt properties based on the block insertion and its surrounding context.

This method can be useful when the same block must display differently in different situations.

However, its behavior depends on:

  • The properties of objects inside the block
  • The layer on which the block is inserted
  • The properties assigned to the block reference
  • The way nested blocks are configured

Linetype Assigned Directly to an Object

A linetype can also be assigned directly to an individual object.

This creates an object-level override that replaces the layer linetype.

Direct assignments may be useful for occasional exceptions, but excessive use can make drawings difficult to manage.

Common problems include:

  • Objects that do not follow layer standards
  • Inconsistent plotting
  • Difficult global updates
  • Confusing property combinations
  • More time required for auditing

For most drawings, ByLayer should remain the default.

The CELTYPE System Variable

The CELTYPE system variable defines the current linetype assigned to newly created objects.

Its default value is normally:

BYLAYER

CELTYPE should not be confused with CELTSCALE.

  • CELTYPE controls the current linetype.
  • CELTSCALE controls the linetype scale applied to new objects.

Keeping CELTYPE set to BYLAYER helps maintain consistent layer-based standards.

How Linetype Scale Affects the Pattern

Why Linetype Patterns Can Look Too Large or Too Small

A linetype definition contains fixed pattern values, but those values must be scaled to match the drawing.

A pattern may appear incorrect when:

  • The drawing uses different units.
  • The wrong LIN file was loaded.
  • The global linetype scale is unsuitable.
  • The object has a scale override.
  • The annotation scale affects the display.
  • The viewport has a different scale.
  • Model Space and Paper Space settings are inconsistent.

A hidden line that looks correct in one drawing may appear continuous in another drawing if the two files use different unit systems or scale settings.

LTSCALE

The LTSCALE system variable controls the global linetype scale for the drawing.

Increasing LTSCALE generally makes the pattern elements longer.

Decreasing LTSCALE generally makes them shorter and more frequent.

For example:

  • A very high value may create dashes and gaps that are too large.
  • A very low value may make the pattern so dense that it appears continuous.

CELTSCALE

The CELTSCALE system variable controls the linetype scale assigned to newly created objects.

It works in combination with LTSCALE.

The effective scale of a new object is influenced by both:

  • The drawing’s global scale
  • The object’s individual linetype scale

Existing objects can also have their own linetype scale property.

MSLTSCALE

The MSLTSCALE system variable controls how linetypes respond to annotation scale in Model Space.

It is useful when working with annotated drawings that must display consistently at different scales.

PSLTSCALE

The PSLTSCALE system variable controls the display of linetypes through Paper Space viewports.

When configured correctly, linetypes can maintain a consistent printed appearance across viewports with different scales.

For example, a hidden line should have a similar dash size on the sheet whether the viewport is displayed at 1:20 or 1:100.

Because linetype scaling includes several interacting variables, it should be covered in dedicated articles about:

  • LTSCALE
  • CELTSCALE
  • MSLTSCALE
  • PSLTSCALE
  • Metric vs. imperial scaling

How CAD Linetypes Appear on Different Objects

Lines

A standard line contains one straight segment.

The pattern is applied from one endpoint to the other.

If the line is too short to contain a complete pattern, it may show only one dash or appear continuous.

Polylines

A polyline may contain multiple connected segments.

The pattern can:

  • Restart at each vertex
  • Continue through the vertices
  • Change appearance on very short segments
  • Become uneven around tight corners

The result depends on the Linetype Generation property and the PLINEGEN setting.

Arcs and Circles

On arcs and circles, the pattern follows the actual curved path.

Very small circles and tight arcs may not contain enough length for a complete sequence.

As a result, the object may display:

  • Only a few dashes
  • Partial gaps
  • A nearly continuous pattern

Splines and Irregular Curves

A linetype can follow a spline or irregular curve.

However, complex patterns may be difficult to read on:

  • Sharp curves
  • Tight loops
  • Short curve segments
  • Highly irregular geometry

Simple patterns usually provide more reliable results on complex curves.

Blocks

Objects inside blocks retain their internal property configuration.

Their final appearance may depend on:

  • The object layer
  • The block insertion layer
  • ByLayer settings
  • ByBlock settings
  • Direct overrides
  • Block scale

A block can therefore display differently depending on how its internal objects were created.

External References

External references can introduce additional linetype definitions into a host drawing.

Differences in:

  • Drawing units
  • LTSCALE
  • Viewport settings
  • Object scale
  • Source-file standards

can cause referenced linetypes to appear different from native objects in the host drawing.

Multilines

A multiline is controlled through a multiline style.

Each element in the style can have its own:

  • Offset
  • Color
  • Linetype

These settings are managed with MLSTYLE.

The linetype is therefore part of the multiline style definition rather than a simple property assigned to the complete multiline object.

Hatches

Hatches use patterns defined in .PAT files.

Their appearance is mainly controlled through:

  • Hatch pattern
  • Hatch scale
  • Hatch angle
  • Origin
  • Associativity

AutoCAD also includes the HPLINETYPE system variable, which controls whether non-continuous object linetypes are displayed within hatch lines.

In most practical situations, however, the internal appearance of a hatch should be managed through its hatch pattern rather than through a .LIN definition.

CAD Linetypes vs. Other Object Properties

Linetype vs. Lineweight

Linetype controls the visual pattern.

Lineweight controls thickness.

A line can therefore be:

  • Continuous and thick
  • Continuous and thin
  • Dashed and thick
  • Dashed and thin

These two properties are independent.

Linetype vs. Color

Color controls the displayed color of the object.

In a CTB-based plotting system, color may also determine printed properties such as lineweight or screening.

The linetype controls the dash-and-gap sequence, not the color.

Linetype vs. Plot Style

Plot styles control how objects are printed.

A CTB or STB file may control:

  • Printed color
  • Lineweight
  • Screening
  • Grayscale
  • End styles
  • Join styles

Plot styles do not normally define the actual sequence of dashes, gaps or dots. That information comes from the linetype definition.

Linetype vs. Layer

A layer organizes drawing objects and can supply inherited properties such as:

  • Color
  • Linetype
  • Lineweight
  • Transparency
  • Plot status

The layer is therefore a management structure, while the linetype is one of the properties that can be assigned to it.

Comparison Table

Property Main Function
Linetype Controls the sequence of dashes, gaps, dots, text or shapes
Lineweight Controls displayed or plotted thickness
Color Controls object color and may influence CTB-based plotting
Plot style Controls selected aspects of printed appearance
Layer Organizes objects and supplies inherited properties

Examples of Linetype Use by Industry

Architecture

Architectural drawings may use linetypes to represent:

  • Hidden walls
  • Overhead cabinets
  • Roof projections
  • Demolition work
  • Property boundaries
  • Fire-rated partitions
  • Elements below the plan cut
  • Future construction

Mechanical Engineering

Mechanical drawings commonly use linetypes for:

  • Hidden edges
  • Centerlines
  • Cutting planes
  • Symmetry axes
  • Alternate positions
  • Paths of motion
  • Adjacent parts

Civil Engineering and Surveying

Civil and survey drawings use linetypes for:

  • Property lines
  • Easements
  • Road centerlines
  • Existing utilities
  • Proposed utilities
  • Construction limits
  • Municipal boundaries
  • Drainage networks

Electrical and MEP Drawings

Electrical, mechanical and plumbing drawings may use different patterns for:

  • Electrical circuits
  • Communication cables
  • Gas pipes
  • Water pipes
  • Drainage lines
  • Fire protection systems
  • HVAC services
  • Underground networks

Landscape Design

Landscape and site drawings may use linetypes to identify:

  • Fences
  • Irrigation lines
  • Planting boundaries
  • Grading limits
  • Site boundaries
  • Existing features
  • Proposed features
  • Underground services

Why Does a CAD Linetype Appear Continuous?

A dashed or complex linetype may appear continuous for several reasons.

The Linetype Has Not Been Loaded

Assigning a linetype requires the definition to exist in the drawing.

Use the LINETYPE command or the command-line version -LINETYPE to load the required definition.

The Object Is Too Short

A short object may not contain enough length for a complete dash-and-gap sequence.

Try:

  • Extending the object
  • Reducing its object linetype scale
  • Adjusting LTSCALE
  • Testing another pattern

The Linetype Scale Is Too Small

When the pattern is too dense, the dashes and gaps may visually merge.

Increase the relevant scale value gradually.

The Linetype Scale Is Too Large

When the pattern is too large, a short object may display only one long dash.

Reduce the scale value gradually.

The Wrong Unit Definition Was Loaded

An imperial linetype used in a metric drawing may appear extremely small.

A metric linetype used in an imperial drawing may appear extremely large.

Verify whether the definition came from the correct LIN file.

The View Needs to Be Regenerated

After changing some linetype settings, use the REGEN command to refresh the drawing display.

Polyline Generation Is Disabled

A polyline pattern may restart at every vertex if linetype generation is disabled.

Check:

  • The object’s Linetype Generation property
  • The PLINEGEN setting

Paper Space Settings Are Incorrect

A linetype may look correct in Model Space but incorrect in a layout viewport.

Check:

  • PSLTSCALE
  • Viewport scale
  • Annotation scale
  • MSLTSCALE
  • Object linetype scale

A Required Support File Is Missing

A complex linetype may depend on:

  • A font
  • A text style
  • An SHX shape file

If the support file is unavailable, the text or shape may not display correctly.

Standard and Custom CAD Linetypes

When to Use Standard Linetypes

Standard linetypes are suitable when a project requires:

  • General technical documentation
  • Maximum compatibility
  • Recognized drafting conventions
  • Reliable printing
  • Easy file exchange
  • Simple maintenance

They are normally sufficient for visible, hidden, center, phantom and basic boundary lines.

When to Create a Custom Linetype

A custom linetype may be useful for:

  • Specialized utility networks
  • Company CAD standards
  • Industry-specific symbols
  • Repeated service labels
  • Unique property boundaries
  • Custom fence patterns
  • Directional flow lines
  • Specialized technical documentation

Custom linetypes can reduce the need for repeated notes and manually inserted symbols.

Risks of Custom Linetypes

Custom patterns can create problems when they are not managed correctly.

Common risks include:

  • Missing SHX shape files
  • Missing fonts
  • Incorrect text styles
  • Metric and imperial scale problems
  • Inconsistent text orientation
  • Poor display on curved objects
  • Software compatibility differences
  • Excessively complex patterns
  • Unreadable printed output

Custom linetypes should be tested before being added to a company-wide standards library.

CAD Linetype Compatibility

LIN-based linetypes are supported by AutoCAD and many DWG-compatible CAD programs.

Common platforms include:

  • AutoCAD
  • AutoCAD LT
  • AutoCAD for Mac
  • BricsCAD
  • DraftSight
  • ZWCAD
  • GstarCAD
  • progeCAD
  • nanoCAD
  • CMS IntelliCAD

Simple patterns containing only dashes, gaps and dots generally provide the best compatibility.

Complex linetypes may behave differently depending on:

  • Font support
  • SHX shape support
  • Text style configuration
  • Drawing units
  • Software version
  • Pattern interpretation

Before distributing a custom linetype library, test it in the main CAD applications used by the intended audience.

Important CAD Linetype Commands and Variables

The following commands and variables are useful when managing linetypes.

Command or Variable Purpose
LINETYPE Opens the Linetype Manager
-LINETYPE Loads, sets, creates or manages linetypes from the command line
LTSCALE Sets the global linetype scale
CELTYPE Sets the current linetype for new objects
CELTSCALE Sets the linetype scale for new objects
PLINEGEN Controls pattern continuity through polyline vertices
MEASUREMENT Selects imperial or metric support-file conventions
HPLINETYPE Controls non-continuous linetypes in hatch lines
PURGE Removes unused linetype definitions and other unused named objects
REGEN Regenerates the drawing display

These controls help users load, assign, scale, display and clean up linetype definitions.

Best Practices for Using CAD Linetypes

Follow these practices to create reliable and readable drawings:

  • Assign linetypes primarily through layers.
  • Keep CELTYPE set to ByLayer unless an exception is required.
  • Avoid unnecessary object-level overrides.
  • Use clear and standardized linetype names.
  • Match the LIN file to the drawing unit system.
  • Maintain separate metric and imperial definitions when necessary.
  • Keep custom patterns simple and readable.
  • Include required fonts and SHX shape files.
  • Use consistent text styles.
  • Test patterns in Model Space and Paper Space.
  • Test all important viewport scales.
  • Verify printed output with the correct plot style.
  • Use REGEN after important display changes.
  • Use PURGE to remove unused definitions.
  • Follow company, client and industry CAD standards.
  • Document custom linetypes in the project standards manual.

A well-managed linetype library should be easy to load, understand, exchange and maintain.

Frequently Asked Questions About CAD Linetypes

What Is a Linetype in CAD?

A linetype is a repeating visual pattern applied to CAD geometry. It may contain dashes, gaps, dots, text or custom shapes.

Does a Dashed Linetype Create Separate Line Segments?

No. A dashed linetype normally changes only the displayed pattern. The underlying line remains one continuous geometric object.

What Is the Difference Between a Line and a Linetype?

A line is a geometric object with a measurable length and position. A linetype is a display property that controls how that geometry appears.

What Is a LIN File?

A LIN file is a plain-text file containing one or more linetype definitions. It can specify dashes, gaps, dots, text references and shape references.

What Is the Difference Between Simple and Complex Linetypes?

Simple linetypes contain only dashes, gaps and dots. Complex linetypes may also include embedded text or SHX shapes.

Why Does My CAD Linetype Appear Continuous?

The object may be too short, the scale may be incorrect, the linetype may not be loaded or the wrong metric or imperial definition may have been used.

Can I Create My Own AutoCAD Linetype?

Yes. Custom linetypes can be written in a LIN file. They can contain basic dash patterns, text or compiled SHX shapes.

Are AutoCAD LIN Files Compatible With Other CAD Programs?

Many DWG-compatible applications support standard LIN files. Simple patterns are generally more portable than complex patterns that depend on custom fonts or shape files.

Are Linetypes Stored in the DWG File?

Yes. Once a linetype is loaded, its definition is normally stored in the drawing. Complex patterns may still require external fonts or SHX shape files.

Why Does a Linetype Look Different in Model Space and Paper Space?

Model Space and Paper Space use different scale contexts. Variables such as LTSCALE, MSLTSCALE and PSLTSCALE influence how patterns appear in layouts and viewports.

Do Hatches Use LIN Files?

Hatches primarily use .PAT pattern files. Their internal line arrangement is controlled by the hatch pattern, scale and angle rather than by a standard LIN definition.

Do Multilines Use Standard Object Linetypes?

Multilines use linetypes assigned to the individual elements of their multiline style. These settings are managed through MLSTYLE.

Conclusion

A CAD linetype is a repeating graphical pattern used to communicate technical meaning in a drawing. It can contain dashes, gaps, dots, text or custom SHX shapes.

The final appearance of a linetype depends mainly on:

  1. The linetype definition
  2. The assignment method
  3. The drawing units
  4. The global and object scale settings
  5. The Model Space and Paper Space configuration

Simple linetypes provide strong compatibility and are suitable for most technical drawings. Complex linetypes add text and symbols but may require additional fonts, text styles or SHX shape files.

For reliable results, use ByLayer assignments, load the correct metric or imperial definition, manage scale variables carefully and test every important pattern in both Model Space and Paper Space.

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