PSLTSCALE vs. MSLTSCALE: Managing Linetypes in Model Space and Layouts

A dashed, hidden, center, or complex linetype may look correct in Model Space but appear very different in a layout. The dashes may become too long, too short, irregular, or so closely spaced that the line appears continuous.

These display problems often come from the interaction between PSLTSCALE, MSLTSCALE, LTSCALE, the current annotation scale, and the individual linetype scale assigned to objects.

The main distinction is straightforward:

  • MSLTSCALE controls how linetypes are displayed on the Model tab.
  • PSLTSCALE controls how model-space linetypes appear through layout viewports.
  • LTSCALE applies a global linetype scale factor to the drawing.
  • CELTSCALE defines the linetype scale assigned to new objects.

Correctly configuring these settings helps hidden lines, centerlines, boundaries, utility lines, and custom linetypes remain readable in both the drawing environment and the final printed sheet.

What Are PSLTSCALE and MSLTSCALE?

PSLTSCALE and MSLTSCALE control linetype display in two different drawing environments.

They do not change the geometry, the assigned linetype, or the original pattern stored in the .LIN file. They only affect how AutoCAD displays the pattern.

Variable Affected area Scaling reference Main purpose
MSLTSCALE Model tab Current annotation scale defined by CANNOSCALE Controls linetype appearance while working in Model Space
PSLTSCALE Layout viewports Paper Space units and viewport scale Controls linetype consistency between viewports
LTSCALE Entire drawing Global scale factor Adjusts the overall size of linetype patterns
CELTSCALE Newly created objects Individual object multiplier Sets the default linetype scale for new objects

How PSLTSCALE Works in Layout Viewports

PSLTSCALE stands for Paper Space Linetype Scale.

It controls how linetypes assigned to model-space objects are displayed through layout viewports.

The variable accepts two values:

  • PSLTSCALE = 0
  • PSLTSCALE = 1

The correct value depends on whether the linetype pattern should remain consistent in model units or in paper units.

PSLTSCALE = 1: Consistent Appearance on the Sheet

When PSLTSCALE = 1, AutoCAD adjusts linetype patterns according to the viewport scale so that their appearance remains consistent in Paper Space.

Consider a layout containing:

  • a general plan at 1:100;
  • a section at 1:50;
  • a detail at 1:20.

Without viewport compensation, the same hidden line would appear with different dash lengths in each viewport.

With PSLTSCALE = 1, AutoCAD compensates for these scale differences. The dashes appear approximately the same length on the printed sheet, even though the viewports use different scales.

This is generally the preferred setting when:

  • several viewport scales are used on the same layout;
  • dash lengths must remain visually consistent on paper;
  • the drawing is plotted from layouts;
  • office standards define linetypes according to their printed appearance.

PSLTSCALE = 0: Patterns Remain Based on Model Units

When PSLTSCALE = 0, AutoCAD does not compensate for viewport scale.

The linetype pattern remains based on the model-space dimensions of the pattern. As a result, its printed appearance changes according to the viewport scale.

For example, a dash representing 100 drawing units appears:

  • larger in a viewport at 1:50;
  • smaller in a viewport at 1:100.

This setting may be useful when the pattern represents an actual model-space distance, such as:

  • survey markings;
  • mapping patterns;
  • utility lines;
  • civil engineering conventions;
  • custom linetypes with real-world pattern dimensions.

For most architectural and mechanical drawing layouts, however, PSLTSCALE = 1 provides a more uniform result.

PSLTSCALE Comparison

Viewport scale PSLTSCALE = 0 PSLTSCALE = 1
1:20 Pattern appears larger on paper Pattern maintains a consistent paper-space appearance
1:50 Pattern changes with viewport magnification Pattern maintains a consistent paper-space appearance
1:100 Pattern appears smaller on paper Pattern maintains a consistent paper-space appearance

The difference can be summarized as follows:

  • PSLTSCALE = 0 favors consistency in model units.
  • PSLTSCALE = 1 favors consistency on the printed sheet.

PSLTSCALE Can Differ Between Layouts

The value of PSLTSCALE can be stored separately in each layout.

A drawing may therefore contain:

Layout A: PSLTSCALE = 1
Layout B: PSLTSCALE = 0

This explains why linetypes can appear correct in one layout but incorrect in another.

When checking an existing drawing or template, activate each layout and confirm its PSLTSCALE value.

How MSLTSCALE Works in Model Space

MSLTSCALE stands for Model Space Linetype Scale.

It determines whether linetypes displayed on the Model tab are scaled according to the current annotation scale.

The variable accepts two values:

  • MSLTSCALE = 0
  • MSLTSCALE = 1

MSLTSCALE = 1: Linetypes Follow CANNOSCALE

When MSLTSCALE = 1, the linetype display in Model Space depends on the current annotation scale stored in CANNOSCALE.

CANNOSCALE is the active annotation scale shown in the AutoCAD status bar. Typical values include:

  • 1:20
  • 1:50
  • 1:100
  • 1/4″ = 1′-0″
  • 1/8″ = 1′-0″

When CANNOSCALE changes, the visible linetype pattern on the Model tab also changes.

For example:

MSLTSCALE = 1
CANNOSCALE = 1:50

produces a different Model Space display from:

MSLTSCALE = 1
CANNOSCALE = 1:100

The geometry does not change. The object retains the same linetype and scale properties. Only the Model Space display is adjusted.

This setting is useful when:

  • annotative text and dimensions are used;
  • the current annotation scale corresponds to the intended plotting scale;
  • users want a more representative preview while working in Model Space.

MSLTSCALE = 0: Annotation Scale Is Ignored

When MSLTSCALE = 0, CANNOSCALE does not affect linetype display on the Model tab.

The visible pattern is controlled primarily by:

  • LTSCALE;
  • the object’s individual Linetype scale;
  • the dimensions in the .LIN definition;
  • the length and geometry of the object.

This setting is useful when:

  • annotation scaling is not used;
  • drawings are plotted directly from Model Space;
  • patterns must remain based on drawing units;
  • users do not want linetypes to change when CANNOSCALE changes.

Limits of MSLTSCALE

Only one annotation scale can be current at a time.

A Model Space drawing may contain:

  • a general plan intended for 1:100;
  • a detail intended for 1:20;
  • a section intended for 1:50.

MSLTSCALE cannot preview all three output scales simultaneously. It only uses the current CANNOSCALE value.

For that reason, the final linetype check should always be completed in the layouts.

How PSLTSCALE, MSLTSCALE, and LTSCALE Work Together

LTSCALE remains the global linetype scale factor for the drawing.

A simplified representation of the display process is:

Displayed pattern = LIN definition × LTSCALE × object linetype scale × space-dependent scaling

The space-dependent factor may include:

  • CANNOSCALE when MSLTSCALE is set to 1;
  • viewport compensation when PSLTSCALE is set to 1;
  • normal viewport magnification when PSLTSCALE is set to 0.

This is a simplified explanation rather than a complete mathematical formula for every AutoCAD object type.

What LTSCALE Controls

LTSCALE adjusts the size of linetype patterns globally.

Examples:

  • LTSCALE = 0.5 makes pattern elements smaller.
  • LTSCALE = 1 uses the standard pattern size.
  • LTSCALE = 2 makes pattern elements larger.

Changing LTSCALE affects all eligible patterned objects in the drawing.

It should not be used to correct a problem limited to one viewport or one object.

What CELTSCALE Controls

CELTSCALE defines the individual linetype scale assigned to newly created objects.

For most standardized drawings, use:

CELTSCALE = 1

A different value should only be used when new objects need a deliberate individual scale override.

Existing Object Linetype Scale

Each eligible object also has an individual Linetype scale property in the Properties palette.

For example:

Object A Linetype scale = 1
Object B Linetype scale = 10

Object B displays a pattern ten times larger than Object A, even when both use the same layer and linetype.

When only one object looks incorrect, check its individual property before changing global variables.

Keeping the object linetype scale at 1.0 whenever possible makes drawings easier to maintain and audit.

For drawings created at full size in Model Space and plotted from Paper Space layouts, the following values provide a practical starting point:

LTSCALE = 1
CELTSCALE = 1
MSLTSCALE = 1
PSLTSCALE = 1
Object Linetype Scale = 1

These values assume that:

  • the correct metric or imperial linetype definitions are loaded;
  • the drawing units are correctly configured;
  • the layout viewports use exact scales;
  • the office template was designed around these values.

A reliable workflow is:

  1. Draw all geometry at 1:1 full size in Model Space.
  2. Select the intended annotation scale through CANNOSCALE.
  3. Create sheets in Paper Space.
  4. Assign an exact scale to every viewport.
  5. Lock each viewport.
  6. Confirm PSLTSCALE = 1 in each layout.
  7. Run REGENALL.
  8. Verify the result in Plot Preview and in the exported PDF.

The value LTSCALE = 1 is a starting point, not a universal requirement. Some custom linetype libraries or office standards may require another global value.

Metric and Imperial Linetype Definitions

AutoCAD commonly provides two standard linetype files:

acad.lin
acadiso.lin

In general:

  • acad.lin contains linetype definitions intended for imperial drawings;
  • acadiso.lin contains ISO definitions commonly used in metric drawings.

Using the wrong definition file can make a pattern appear far too large or too small.

The MEASUREMENT Variable

The system variable MEASUREMENT determines whether AutoCAD uses imperial or metric hatch and linetype definition files by default.

Its values are:

MEASUREMENT = 0

Uses imperial definitions by default.

MEASUREMENT = 1

Uses metric definitions by default.

When the LINETYPE command is used and the user selects Load, this variable helps determine whether AutoCAD initially references acad.lin or acadiso.lin.

Before correcting scale values, verify:

  1. the drawing units;
  2. the MEASUREMENT value;
  3. the source .LIN file used for the linetype.

Changing LTSCALE to an extreme value may hide a metric-imperial mismatch without correcting it.

MEASUREINIT

MEASUREINIT defines the initial measurement system for new drawings that do not use a template.

It is less important in an established .DWT workflow because template settings normally take precedence. However, it can affect the starting environment of newly created drawings.

For consistent production work, define the measurement system directly in the company template.

Step-by-Step Setup for Consistent Linetypes

Step 1 — Verify the Drawing Environment

Enter:

UNITS

Confirm whether the drawing uses:

  • millimeters;
  • meters;
  • inches;
  • feet;
  • another unit system.

Then enter:

MEASUREMENT

Use:

0

for imperial definitions, or:

1

for metric definitions.

Confirm that the correct linetype was loaded from either acad.lin, acadiso.lin, or an approved custom .LIN file.

Step 2 — Check Global and Object Scale Values

Enter:

LTSCALE

Begin with the standard value required by the drawing template.

Then verify:

CELTSCALE = 1

Select a problematic object and check its Linetype scale in the Properties palette.

Avoid changing several variables at once. Identify whether the problem affects:

  • every linetype;
  • one layer;
  • one object;
  • one viewport;
  • one layout.

Step 3 — Configure Model Space Display

Enter:

MSLTSCALE

Use 1 when the Model tab display should follow the annotation scale.

Use 0 when the annotation scale should not affect the linetype display.

When MSLTSCALE is set to 1, check the current value of:

CANNOSCALE

Set it to the intended output scale and test several common linetypes, such as:

  • HIDDEN
  • CENTER
  • DASHED
  • custom text or shape linetypes

Use a line long enough to show several complete pattern repetitions.

Step 4 — Configure Each Layout

Activate a layout and enter:

PSLTSCALE

Use 1 when linetypes should have a consistent appearance across different viewport scales.

Repeat this check in every layout.

Select each viewport boundary and verify its:

  • Standard scale;
  • Custom scale;
  • locked or unlocked status.

Lock the viewport after its scale is confirmed.

Step 5 — Regenerate the Drawing

Run:

REGEN

to regenerate the current viewport.

Run:

REGENALL

to regenerate all viewports.

After changing PSLTSCALE, MSLTSCALE, LTSCALE, CANNOSCALE, or object linetype properties, REGENALL is normally the safest command.

Step 6 — Check the Final Output

Verify the linetypes in:

  1. the layout;
  2. Plot Preview;
  3. the exported PDF;
  4. a printed sample when necessary.

The Model tab alone does not provide a reliable representation of every layout scale.

Troubleshooting Linetype Problems

Linetypes Look Correct in Model Space but Wrong in Layouts

Check the following:

  1. Activate the affected layout.
  2. Confirm PSLTSCALE.
  3. Verify the viewport scale.
  4. Run REGENALL.
  5. Check the individual object linetype scale.
  6. Compare the PSLTSCALE value with the other layouts.

A correct Model Space display does not guarantee a correct layout display because MSLTSCALE and PSLTSCALE control different environments.

Linetypes Look Different Between Viewports

The most common causes are:

  • PSLTSCALE = 0;
  • different viewport scales;
  • viewports not regenerated;
  • different object-level scale overrides;
  • separate layouts using different PSLTSCALE values.

When consistent printed dash lengths are required, use PSLTSCALE = 1 and run REGENALL.

Linetypes Appear Continuous

A dashed line may appear continuous when:

  • the pattern is too small for the current zoom level;
  • the pattern is too large for the object;
  • the object is too short to show a complete cycle;
  • LTSCALE is unsuitable;
  • the individual object scale is unsuitable;
  • the wrong metric or imperial definition is loaded;
  • the display has not been regenerated.

Test the linetype on a long temporary line before changing global settings.

A Polyline Pattern Restarts at Every Vertex

By default, a linetype pattern may restart at each polyline vertex. This can produce irregular dashes, especially on polylines containing many short segments.

Use:

PLINEGEN = 1

to generate the linetype continuously along the entire polyline.

The same setting can be changed for an existing polyline through the Properties palette by enabling Linetype generation.

Use:

PLINEGEN = 0

when the pattern should restart at every vertex.

For most long dashed or centerline polylines, PLINEGEN = 1 provides a cleaner result.

Linetypes Change When the Annotation Scale Changes

This is expected when:

MSLTSCALE = 1

In this mode, the Model Space display follows CANNOSCALE.

Use:

MSLTSCALE = 0

when the linetype display should remain independent of the current annotation scale.

This affects the Model tab only. It does not replace PSLTSCALE in layouts.

Paper Space and Model Space Objects Do Not Match

A layout may contain:

  • objects drawn directly in Paper Space;
  • model-space objects displayed through a viewport.

With PSLTSCALE = 1, their linetype patterns can display with a similar scale on the sheet.

If they do not match, check:

  • PSLTSCALE;
  • LTSCALE;
  • individual object scales;
  • whether both objects use the same linetype definition;
  • whether REGENALL has been run.

One Layout Looks Correct but Another Does Not

Check PSLTSCALE separately in each layout.

Also verify:

  • viewport scales;
  • object overrides;
  • regeneration;
  • the loaded linetype definitions.

Do not assume that changing PSLTSCALE in one layout updates every layout in the drawing.

Linetypes Inside Blocks and Nested Blocks

Linetypes inside blocks can sometimes produce unexpected results.

A line inside a block may be affected by:

  • the linetype assigned to the original object;
  • the object’s individual linetype scale;
  • the layer settings;
  • the scale of the inserted block reference;
  • nested block scaling;
  • the global LTSCALE value;
  • PSLTSCALE or MSLTSCALE display behavior.

A block inserted with a scale other than 1 may visually change the linetype pattern of its internal geometry.

Nested blocks can make this effect more difficult to identify because several block scales may be multiplied together.

When a linetype inside a block looks incorrect:

  1. Open the block in Block Editor.
  2. Inspect the internal object’s linetype and individual scale.
  3. Check the insertion scale of the block reference.
  4. Check any nested block references.
  5. Run REGENALL.
  6. Update or redefine the block if necessary.

Exploding the block can help identify the cause, but it should normally be used only as a diagnostic step. Updating the block definition is preferable when the block must remain reusable.

Common Mistakes to Avoid

Using LTSCALE to Fix One Viewport

LTSCALE is global and affects the entire drawing.

When only one viewport looks incorrect, check PSLTSCALE, viewport scale, object properties, and regeneration before changing LTSCALE.

Applying Individual Overrides to Many Objects

Changing the linetype scale of many separate objects creates an inconsistent drawing.

Keep the individual scale at 1.0 whenever possible and control the drawing through standard variables and approved .LIN files.

Confusing MSLTSCALE With PSLTSCALE

MSLTSCALE controls Model Space display.

PSLTSCALE controls linetype scaling through layout viewports.

They are related, but one cannot replace the other.

Confusing PSLTSCALE With Viewport Scale

PSLTSCALE does not set the viewport scale.

A viewport may be set to 1:20, 1:50, or 1:100 independently. PSLTSCALE only controls how linetypes are adjusted when viewed through that viewport.

Ignoring MEASUREMENT

A metric-imperial mismatch can create major linetype scale problems.

Check MEASUREMENT and the source .LIN file before applying extreme LTSCALE values.

Ignoring PLINEGEN

If a pattern restarts at every polyline vertex, changing PSLTSCALE or LTSCALE will not correct the underlying problem.

Use PLINEGEN = 1 or enable Linetype generation for the polyline.

Forgetting REGENALL

AutoCAD may continue displaying an outdated pattern until the drawing is regenerated.

Run REGENALL after changing linetype-related variables or viewport settings.

Checking Only the Model Tab

The final result should always be inspected in the layout and Plot Preview.

A line can look correct in Model Space and still appear incorrect in the printed sheet.

Best Practices for CAD Templates and Standards

Store the Settings in a DWT Template

A company .DWT template should contain:

  • approved metric or imperial linetypes;
  • standard layers;
  • LTSCALE;
  • CELTSCALE;
  • MSLTSCALE;
  • predefined annotation scales;
  • layouts;
  • PSLTSCALE values;
  • viewport and plot settings.

Check PSLTSCALE in every predefined layout before distributing the template.

Keep Object Linetype Scale at 1

Standardizing individual object scale at 1.0 simplifies:

  • troubleshooting;
  • drawing audits;
  • block management;
  • copying objects between files;
  • CAD standards enforcement.

Use overrides only for genuine graphic exceptions.

Test Several Viewport Scales

Create a test layout containing viewports at several common scales, such as:

  • 1:20
  • 1:50
  • 1:100

Include:

  • hidden lines;
  • centerlines;
  • dashed boundaries;
  • complex linetypes;
  • polylines with PLINEGEN enabled;
  • lines inside blocks.

Export the layout to PDF and check the actual printed appearance.

Document the Office Standard

A linetype standard should specify:

  • the approved .LIN files;
  • MEASUREMENT value;
  • drawing units;
  • default LTSCALE;
  • default CELTSCALE;
  • required MSLTSCALE setting;
  • required PSLTSCALE setting;
  • use of CANNOSCALE;
  • PLINEGEN rules;
  • permitted object-scale overrides;
  • block and nested-block guidelines;
  • quality-control procedures.

Quick Decision Guide

Situation Recommended action
Linetypes should look consistent across different viewport scales Set PSLTSCALE = 1
Linetype patterns must remain based on model units Set PSLTSCALE = 0
Model Space display should follow annotation scale Set MSLTSCALE = 1 and check CANNOSCALE
Annotation scale should not affect Model Space linetypes Set MSLTSCALE = 0
A pattern restarts at every polyline vertex Set PLINEGEN = 1
Metric linetypes load incorrectly Check MEASUREMENT = 1 and acadiso.lin
Imperial linetypes load incorrectly Check MEASUREMENT = 0 and acad.lin
One object looks incorrect Check its Linetype scale property
One layout looks incorrect Check PSLTSCALE in that layout
Changes are not visible Run REGENALL
A linetype inside a block looks incorrect Check internal object scale, block scale, and nested references

Frequently Asked Questions

What Is the Difference Between PSLTSCALE and MSLTSCALE?

MSLTSCALE controls whether linetypes on the Model tab follow the current annotation scale defined by CANNOSCALE.

PSLTSCALE controls how model-space linetypes are adjusted when displayed through Paper Space viewports.

Should PSLTSCALE Be Set to 0 or 1?

Use PSLTSCALE = 1 when linetypes should have a consistent printed appearance across viewports with different scales.

Use PSLTSCALE = 0 when patterns must remain based on actual model-space units.

Should MSLTSCALE Be Set to 0 or 1?

Use MSLTSCALE = 1 when the Model tab display should follow CANNOSCALE.

Use MSLTSCALE = 0 when annotation scale should not affect Model Space linetypes.

Why Do Dashed Lines Appear Continuous?

The object may be too short, the pattern scale may be unsuitable, the wrong .LIN definition may be loaded, or the drawing may need regeneration.

Check LTSCALE, the object linetype scale, MEASUREMENT, and the source linetype file.

Why Does a Polyline Linetype Restart at Every Vertex?

The polyline’s linetype generation is disabled.

Set:

PLINEGEN = 1

or enable Linetype generation in the Properties palette.

Why Does One Layout Look Different From Another?

PSLTSCALE may have a different value in each layout. Activate each layout, confirm the setting, and run REGENALL.

Final Recommendations

For a typical workflow based on full-size Model Space geometry and Paper Space plotting:

  • use the correct metric or imperial .LIN definitions;
  • verify MEASUREMENT;
  • keep CELTSCALE and individual object scales at 1;
  • use MSLTSCALE = 1 when Model Space should follow CANNOSCALE;
  • use PSLTSCALE = 1 for consistent layout viewport patterns;
  • use PLINEGEN = 1 for continuous linetype generation along polylines;
  • check block and nested-block scales when internal linetypes appear incorrect;
  • run REGENALL after making changes;
  • verify the final result in the layout and exported PDF.

The most important distinction remains:

  • MSLTSCALE controls linetype display on the Model tab.
  • PSLTSCALE controls linetype scaling through layout viewports.
  • LTSCALE controls the global pattern size.
  • CANNOSCALE defines the active annotation scale.
  • MEASUREMENT controls the default metric or imperial definition environment.
  • PLINEGEN controls whether a polyline pattern continues through its vertices.

When these variables are configured consistently, linetypes remain predictable in Model Space, layouts, viewports, blocks, and printed sheets.

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