To draw a straight line in AutoCAD, you can use drawing aids like Ortho mode or Polar Tracking to constrain the angle to horizontal, vertical, or specific increments.
Drawing perfectly straight lines (either horizontal or vertical) or lines at predefined angles in AutoCAD is straightforward using built-in drafting tools. These tools help you maintain precision and accuracy in your drawings.
Using Ortho Mode for Horizontal and Vertical Lines
One of the easiest ways to draw straight horizontal or vertical lines is by using Ortho mode.
- Activate Ortho: While using a line command (like the
LINEcommand), you can toggle Ortho mode on or off by pressing the F8 key. When Ortho is on, the line you are drawing will be constrained to be either perfectly horizontal or perfectly vertical relative to your current User Coordinate System (UCS). - Temporary Ortho: If Ortho is off but you need to draw a single segment horizontally or vertically, you can temporarily enable Ortho by holding down the Shift key while specifying the next point of your line.
Steps to Draw a Straight Line with Ortho:
- Start the
LINEcommand (typeLINEorLand press Enter, or click the Line icon). - Click to specify the first point of your line.
- Press F8 to turn Ortho mode ON. (You'll see "ORTHO ON" in the command line).
- Move your cursor in the desired horizontal or vertical direction.
- Type the desired length of the line and press Enter, or click to specify the endpoint.
- (Optional) Press F8 again to turn Ortho mode OFF if needed for subsequent segments.
Using Polar Tracking for Straight Lines and Specific Angles
Another powerful tool is Polar Tracking. While Ortho only locks to 0 and 90 degrees (horizontal and vertical), Polar Tracking allows you to snap to predefined angles, including 0, 90, 180, and 270 degrees, which are essential for drawing straight lines.
- Activate Polar Tracking: You can toggle Polar Tracking on or off by pressing the F10 key. You can also configure Polar Tracking to snap to various angle increments (e.g., 45°, 30°, 15°, etc.).
Steps to Draw a Straight Line with Polar Tracking:
- Start the
LINEcommand. - Click to specify the first point.
- Press F10 to turn Polar Tracking ON. (You'll see "POLAR ON" in the command line).
- Move your cursor towards the desired direction (horizontal or vertical). You will see a dashed alignment path appear when you are close to a tracked angle (like 0° or 90°).
- Type the desired length of the line and press Enter, or click when the alignment path is visible.
Comparing Ortho and Polar Tracking
Both modes help you draw straight lines, but they serve slightly different purposes:
| Feature | Ortho Mode (F8) | Polar Tracking (F10) |
|---|---|---|
| Constraints | Locks to 0°, 90°, 180°, 270° only. | Snaps to predefined angles (including 0°, 90°) |
| Best Use | Primarily for horizontal/vertical lines. | For lines at specific angles, including horizontal/vertical. |
| Temporary Use | Hold Shift key. | Not available via a simple key press during command. |
Practical Tips
- Pay attention to the dynamic input display next to your cursor or the command line; they indicate the current length and angle of the line segment you are drawing.
- Ensure your current layer and line type are set correctly before drawing.
- Check your UCS to ensure horizontal and vertical are as you intend, especially when working in 3D space or on rotated objects.
By utilizing F8 for Ortho mode or F10 for Polar Tracking, you can easily draw precise straight lines in AutoCAD. Remember that you can also hold Shift for temporary horizontal or vertical constraint while drawing.
