Guide

AutoCAD Ortho Mode : A mode that restricts cursor movement to horizontal and vertical

If you need to draw precise horizontal and vertical geometry quickly in AutoCAD, this guide explains Ortho mode in clear, beginner-friendly steps: what it is, why and when to use it, how to turn it on/off, how it interacts with other drafting features, troubleshooting, practical examples, tips, and a FAQ.

What is Ortho Mode?

Ortho Mode (often shown as ORTHO) is an AutoCAD drafting feature that restricts the cursor movement to orthogonal directions — specifically horizontal and vertical — relative to the current User Coordinate system (UCS). When Ortho Mode is active, you can only draw or move in 0° or 90° directions, which enforces perfect orthogonality for lines, polylines, and other drawing actions that support it.

Purpose and benefits

  • Ensure perfectly horizontal or vertical geometry without manual angle input.
  • Speed up routine tasks like drawing walls, grids, schematics, and orthogonal mechanical parts.
  • Reduce errors when precision matters (e.g., architectural floor plans, electrical schematics).
  • Works with common drawing commands (Line, Polyline, Rectangle, Trim, Move, Extend) that respect cursor constraints.
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How to turn Ortho Mode on and off (methods and shortcuts)

  • Toggle from the status bar: click the Ortho Mode icon (usually labeled ORTHO).
  • Press the F8 function key to toggle Ortho Mode on or off quickly.
  • Type the command: enter ORTHO at the command line and press Enter; then enter ON or OFF.
  • Use the system variable: type SETVAR ORTHOMODE 1 to turn on (use 0 to turn off).

Note: When Ortho Mode is on, the cursor movement is constrained to the X and Y axes of the current UCS.

How and when to use Ortho Mode — step-by-step examples

Example 1 — Draw a horizontal or vertical line

  1. Turn Ortho Mode on (F8 or status bar).
  2. Start the Line command: type L + Enter.
  3. Click the start point.
  4. Move the cursor horizontally or vertically — the cursor will snap along the axis — click the endpoint.
  5. Press Enter or Esc to finish.

Example 2 — Draw a simple rectangular room

  1. Turn Ortho Mode on.
  2. Use the Rectangle command (type REC), click the first corner, then drag. Or use Line and draw two perpendicular lines to create corners.
  3. Or use Polyline to draw connected orthogonal edges.

Example 3 — Move or align objects orthogonally

  1. Start the Move command.
  2. Select the object and pick a base point.
  3. With Ortho on, move the cursor horizontally or vertically to align precisely and click for the new location.

Ortho Mode vs Polar tracking and Object snap Tracking

  • Ortho Mode: restricts the cursor to exactly 0° or 90° relative to the UCS. Best when you need strictly horizontal/vertical.
  • Polar Tracking (F10): constrains the cursor to specified angle increments (e.g., 45°, 30°). Use when you need angled constraints other than strictly orthogonal.
  • object snap tracking (OTRACK): provides temporary alignment paths based on object snap points (endpoints, midpoints, intersections). Use when aligning to geometry relationships.
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Use Ortho Mode when you need rigid 0°/90° movement. Use Polar Tracking for angled drafting at custom increments. These features can be used together to improve drafting efficiency.

Editing Ortho Mode and advanced considerations

  • UCS affects Ortho: Ortho aligns with the current UCS axes. If you rotate the UCS, the orthogonal directions rotate with it. To draw relative to world axes, reset the UCS to World (UCS → World).
  • System variable: ORTHOMODE = 1 (on) or 0 (off). Use SETVAR to script or enforce the setting.
  • Macros and aliases: Create a custom keyboard alias or LISP routine to toggle Ortho if you want behavior beyond the default F8 key.
  • Combining with dynamic input: When Dynamic Input is on, you can enter distances with relative coordinates (e.g., @100,0) while Ortho constrains cursor movement visually.
  • Command support: Not every command respects Ortho. Ortho applies to commands that accept cursor-based coordinate entry.

Common errors & fixes (troubleshooting)

  • Problem: Ortho Mode appears active but cursor moves at odd angles.
    • Fix: Check your UCS orientation — Ortho locks to UCS axes. Reset to World if necessary.
  • Problem: F8 does not toggle Ortho.
    • Fix: Check keyboard function key settings (some laptops require Fn+F8), or ensure AutoCAD has focus. Toggle from the status bar or use ORTHO command.
  • Problem: Lines are not perfectly horizontal/vertical even with Ortho on.
    • Fix: Verify Ortho is actually enabled (status bar icon highlighted or ORTHOMODE = 1) and you are using a command that supports Ortho.
  • Problem: Ortho behaves inconsistently with Polar Tracking.
    • Fix: Decide which constraint you want. Turn off Polar Tracking (F10) when you want pure Ortho, or configure Polar angles to match needs.
  • Problem: Ortho seems disabled only during certain operations.
    • Fix: Some editing operations or third-party commands may not honor Ortho. Use manual coordinate entry or ensure you initiate commands that support Ortho locking.
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Tips and best practices

  • Keep Ortho Mode off when you need free drawing; toggle it on (F8) when you must draw horizontal/vertical lines.
  • Use Ortho Mode together with Object Snaps (OSNAP) for precise endpoint alignment.
  • For angled orthogonal geometry (e.g., rotated grids), rotate the UCS and then use Ortho to draw relative to the rotated axes.
  • Use Polar Tracking when you need direction constraints at angles other than 0°/90°.
  • Use Dynamic Input and relative coordinates (@x,y) to enter exact distances while Ortho enforces direction.

FAQ

What exactly does Ortho Mode limit the cursor to?

Ortho Mode restricts cursor movement to horizontal and vertical directions relative to the current UCS — effectively 0° and 90° only.

Can Ortho Mode work at other angles (for example, 45°)?

No. Ortho Mode is limited to orthogonal directions (0°/90°). For other angles, use Polar Tracking with the desired angle increments.

Does Ortho Mode follow a rotated UCS?

Yes — Ortho Mode constrains movement relative to the current UCS. If the UCS is rotated, Ortho-locking aligns to that rotated orientation.

How do I quickly toggle Ortho Mode?

Use the F8 key, click the Ortho Mode icon on the status bar, or type the ORTHO command and set it ON/OFF.

Is there a temporary override key to bypass Ortho without turning it off?

There is no single universal “hold-to-override-Ortho” key applicable in all workflows. For fast switching, toggle F8, create a custom alias/macro, or use Polar Tracking to provide alternate direction constraints when needed.

Why does Ortho sometimes appear not to work?

Common causes: Ortho is off, the command does not support Ortho, the UCS is rotated unexpectedly, or other tracking modes (Polar/Object Snap Tracking) are interfering. Check ORTHOMODE, UCS, and active tracking settings.

Is Ortho Mode available in AutoCAD LT?

Yes — Ortho Mode is a core drafting feature and is available in both AutoCAD and AutoCAD LT.

How can I make Ortho Mode part of my workspace or template?

Set ORTHOMODE = 1 in a startup script, template drawing, or use a startup LISP/acrobat to enable Ortho Mode when a drawing opens.

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