Why Dashed Lines Appear Solid in CAD: LTSCALE, PSLTSCALE & MSLTSCALE Complete Fix
Solve linetype scaling issues in AutoCAD and GstarCAD where dashed, center, or hidden lines display or plot as continuous solid lines in Model Space and Paper Space viewports.
⚡ Quick Answer / Key Takeaway
Set LTSCALE = 1, PSLTSCALE = 1, MSLTSCALE = 1, and CELTSCALE = 1, then type REGENALL (REA) to refresh all viewports. This synchronizes linetype dash lengths automatically with both your annotation scale and paper space viewport scale.
Step-by-Step Instructions & Commands
Step 1: Apply the Universal '1-1-1-1' Linetype Variable Formula
When dashed lines look solid, the dash gaps are either 1,000 times too large or 1,000 times too microscopic for the current scale. Enter these four variables in order: LTSCALE = 1, PSLTSCALE = 1, MSLTSCALE = 1, and CELTSCALE = 1.
Step 2: Match Model Space Annotation Scale and Run REGENALL
In Model Space, set the status bar Annotation Scale (CANNOSCALE) to match your intended print scale (e.g., 1:100). Switch to your Paper Space Layout tab and run REGENALL (shortcut REA). Both Model Space and all scaled viewports will now display identical, properly proportioned dashes.
Step 3: Check Metric (acadiso.lin) vs Imperial (acad.lin) Linetype Definitions
If dashes are still roughly 25.4 times too small in a metric millimeter drawing, the linetype was loaded from the imperial acad.lin / gcad.lin file instead of the metric acadiso.lin / gcadiso.lin file. Run LINETYPE → Load → File, choose the ISO metric `.lin` file, reload all linetypes, and run REGENALL.
Common Issues & Troubleshooting Guide
| Common Failure / Problem | Root Cause & Recommended Solution |
|---|---|
| Polyline with dashed linetype still shows solid along short segments | Select the polyline, open Properties (Ctrl+1), and change 'Linetype generation' from Disabled to Enabled (or set PLINEGEN = 1 for new polylines) so dashes flow continuously across vertices. |
| Linetypes look fine in Layout but change when entering a Viewport | PSLTSCALE is a per-layout variable. Ensure PSLTSCALE is set to 1 inside every individual Paper Space Layout tab and run REGENALL. |
Cross-CAD Compatibility & Alternatives
Both AutoCAD and GstarCAD use the exact same LTSCALE, PSLTSCALE, MSLTSCALE, and PLINEGEN variables. Always verify MEASUREMENT = 1 for metric templates so ISO linetype definitions load by default.
Engineering Best Practices Checklist
- Never manually override individual entity linetype scales (CELTSCALE) to fix a global viewport problem.
- Set PLINEGEN = 1 in all civil and piping templates so multi-vertex polylines display dashed patterns cleanly.
- Always run REGENALL after changing PSLTSCALE; changes do not render until the viewport regenerates.
Related Concepts & Further Learning
Underlying Kernel Mechanics & Automated Prevention Protocol
To permanently prevent recurrence of Why Dashed Lines Appear Solid in CAD: LTSCALE, PSLTSCALE & MSLTSCALE Complete Fix across enterprise project directories, CAD managers must understand how the underlying DWG object database (AcDbDatabase / GcDbDatabase) and graphics display pipeline manage entity handles, symbol tables, and external dependencies:
| Diagnostic Command / Variable | Recommended Production Value | Engineering Function & Impact |
|---|---|---|
| AUDIT / RECOVERALL | Fix Errors = Yes (Y) |
Validates B-tree symbol tables, repairs orphaned dictionary handles, and heals nested Xrefs. |
| -PURGE → Regapps (R) | Verify Each = No (N) |
Strips thousands of unreferenced third-party Registered Application IDs that bloat DWG memory. |
| GRAPHICSCONFIG | Hardware Acceleration = ON | Verifies DirectX 11/12 or OpenGL GPU driver allocation and clears corrupted display cache buffers. |