Creating dashed lines in AutoCAD is a fundamental skill for any CAD user, crucial for conveying information like hidden features, construction lines, or boundaries. This article provides a detailed walkthrough of various methods to achieve this, catering to different versions and levels of experience. We’ll explore line type loading, scaling, and even creating custom dashed line types.
Loading and Applying Dashed Line Types
AutoCAD comes pre-loaded with a range of line types, including various dashed patterns. The first step is usually loading these into your current drawing.
Accessing the Line Type Manager
The Line Type Manager is your central hub for controlling line type definitions within a drawing. You can access it in several ways. The most common is by typing “LINETYPE” (or its shortcut “LT”) in the command line and pressing Enter. Alternatively, you can find it through the ribbon interface, usually under the “Properties” panel on the “Home” tab. Look for the line type control dropdown; clicking “Other…” will open the Line Type Manager.
Loading Line Types
Once the Line Type Manager is open, you’ll likely see only the “Continuous” line type listed. To load dashed line types, click the “Load” button. This opens the “Load or Reload Line Types” dialog box, which displays a list of available line types from the standard AutoCAD library (usually an .lin file).
Scroll through the list and find the dashed line type you want to use. Common options include “DASHED,” “HIDDEN,” and variations like “DASHEDX2” or “HIDDEN2,” which have different dash and space lengths. Select the desired line type and click “OK.” You can select multiple line types by holding down the Ctrl key while clicking. The selected line types will now appear in the Line Type Manager’s list.
Applying the Line Type to Objects
With the desired dashed line type loaded, you can now apply it to objects in your drawing. Select the object(s) you want to modify. Then, in the “Properties” palette (Ctrl+1), find the “Line Type” property. Click the dropdown menu and choose the newly loaded dashed line type. The selected object(s) should now display with the chosen dashed pattern.
Controlling the Appearance of Dashed Lines: Line Type Scale
Simply applying a dashed line type might not always produce the desired result. The dashes might appear too large, too small, or not even be visible at all. This is where Line Type Scale (LTS) comes into play.
Understanding Line Type Scale
Line Type Scale controls the overall scaling of the dash and space lengths in a line type pattern. A larger LTS value will make the dashes and spaces longer, while a smaller value will make them shorter. Think of it as zooming in or out on the line type pattern itself.
Setting the Global Line Type Scale (LTS)
The global LTS affects all line types in the drawing. To set it, type “LTSCALE” (or “LTS”) in the command line and press Enter. You’ll be prompted to enter a new scale factor. Experiment with different values to find the scale that best suits your drawing and viewport scale. A common starting point is 0.5 or 2, but the ideal value depends on the size of your drawing units and the desired appearance of the dashed lines.
Object-Specific Line Type Scale
In some cases, you might want to control the line type scale for individual objects rather than affecting the entire drawing. This can be achieved through the “Properties” palette. Select the object(s) you want to adjust, and in the “Properties” palette, look for the “Line Type Scale” property. Enter a specific scale factor for that object(s) only. This overrides the global LTS for the selected object(s).
Viewport-Specific Line Type Scale (PSLTSCALE)
When working with layouts and viewports, you might notice that dashed lines appear differently in model space and paper space. This is because AutoCAD needs to adjust the line type scale to account for the viewport scale. The PSLTSCALE system variable controls this behavior.
- PSLTSCALE = 1: Line type scaling is adjusted automatically based on the viewport scale. This is the recommended setting for most situations, as it ensures that dashed lines appear consistently regardless of the viewport’s zoom level.
- PSLTSCALE = 0: Line type scaling is not adjusted for viewports. This can lead to dashed lines appearing too small or too large in different viewports.
To set PSLTSCALE, type “PSLTSCALE” in the command line and enter either 0 or 1.
Creating Custom Dashed Line Types
While AutoCAD’s pre-defined line types are sufficient for many tasks, there are times when you need a custom dashed line type with specific dash and space lengths, or even include text or symbols in the pattern.
Understanding Line Type Definition Files (.lin)
Line type definitions are stored in text files with the .lin extension. These files contain the instructions that AutoCAD uses to generate the line type pattern. You can create and edit these files using any text editor, such as Notepad.
Syntax of a Line Type Definition
A line type definition consists of two lines:
- The Header Line: This line starts with an asterisk (*) followed by the line type name and a brief description, separated by a comma. For example:
*MY_DASHED,My Custom Dashed Line. - The Pattern Line: This line starts with the letter “A” (for alignment) followed by a series of numbers separated by commas. Positive numbers represent dashes, negative numbers represent spaces, and 0 represents a dot. For example:
A,1,-0.5,1,-0.5(This creates a dashed line with 1 unit dashes and 0.5 unit spaces).
Creating a Simple Custom Dashed Line
Let’s create a line type with longer dashes and shorter spaces.
- Open a text editor and create a new file.
-
Add the following lines:
*LONG_DASH,Long Dashes and Short SpacesA,2,-0.25
3. Save the file with a .lin extension (e.g., “my_line_types.lin”). Ensure the “Save as type” is set to “All Files” to prevent the text editor from adding a .txt extension. Save it to a location AutoCAD can access. A common place is the AutoCAD support file path.
4. In AutoCAD, open the Line Type Manager and click “Load.”
5. Click “File…” and browse to the location where you saved your .lin file. Select the file and click “Open.”
6. The “Load or Reload Line Types” dialog box will now display your custom line type (“LONG_DASH”). Select it and click “OK.”
You can now apply this custom dashed line type to objects in your drawing as described earlier.
Adding Text or Shapes to Line Types
Custom line types can include text or shapes within the pattern. This involves using special codes in the pattern line.
- [Text,Style=TextStyle,Scale=Height,Rotation=Angle,XOffset=X,YOffset=Y]: This code inserts text into the line type.
- Text: The text to be displayed.
- Style: The text style to use (must be defined in the drawing).
- Scale: The height of the text.
- Rotation: The rotation angle of the text.
- XOffset, YOffset: The offset of the text from the baseline.
- [Shape,ShapeName,Scale=ScaleFactor,Rotation=Angle,XOffset=X,YOffset=Y]: This code inserts a shape (defined in a .shp file) into the line type.
- Shape: The word “Shape”.
- ShapeName: The name of the shape to insert.
- Scale: The scale factor of the shape.
- Rotation: The rotation angle of the shape.
- XOffset, YOffset: The offset of the shape from the baseline.
Creating complex line types with text or shapes requires more advanced knowledge and experimentation. It’s crucial to ensure that the specified text styles and shapes are properly defined in the drawing.
Troubleshooting Dashed Line Display Issues
Sometimes, dashed lines may not display correctly even after following the steps above. Here are some common troubleshooting tips:
- Regenerate the Drawing: Type “REGEN” and press Enter. This forces AutoCAD to recalculate and redraw the display, which can resolve rendering issues.
- Check the Viewport Scale (PSLTSCALE): Ensure PSLTSCALE is set to 1 if you are working with layouts and viewports.
- Verify Object Visibility: Make sure the object is not on a layer that is turned off or frozen.
- Check for Overlapping Objects: If multiple objects are overlapping, the dashed line might be obscured.
- Ensure Correct Units: Verify that your drawing units are set correctly. Incorrect units can affect the appearance of line types.
- Examine the Line Type Definition File: If you created a custom line type, double-check the .lin file for errors in the syntax. Even a small mistake can prevent the line type from loading correctly.
- Consider the Drawing Scale: If your drawing is very large or very small, the default line type scale might not be appropriate. Experiment with different LTS values to find the optimal setting.
- Graphics Card Issues: In rare cases, display problems can be related to your graphics card or driver. Updating your graphics card driver may resolve the issue.
Best Practices for Using Dashed Lines
- Consistency: Use dashed lines consistently throughout your drawing to represent the same type of information.
- Clarity: Choose dashed line types and scales that are easily distinguishable from solid lines and other dashed line types.
- Documentation: Clearly document the meaning of different dashed line types in your drawing’s legend or notes.
- Standardization: Adhere to company or industry standards for line type usage.
- Avoid Overuse: Don’t overuse dashed lines, as too many can make a drawing cluttered and difficult to understand. Use them strategically to highlight important information.
By understanding these methods and best practices, you can effectively use dashed lines in AutoCAD to create clear, informative, and professional drawings.
What are the different ways to create a dashed line in AutoCAD?
There are several methods for creating dashed lines in AutoCAD. One common way is to load a specific linetype, such as “DASHED” or “HIDDEN,” into your drawing. Once loaded, you can select this linetype from the linetype control drop-down menu on the Properties panel or set it as the current linetype before drawing new objects.
Another approach involves adjusting the linetype scale (LTSCALE) to control the spacing and length of the dashes and gaps. This can be done globally for the entire drawing or individually for specific objects using the Properties panel. You can also create custom linetypes with specific dash and space patterns using the Linetype Manager.
How do I load a dashed linetype into my AutoCAD drawing?
To load a dashed linetype, first open the Linetype Manager dialog box. You can access it by typing “LINETYPE” in the command line and pressing Enter. Alternatively, navigate to the “Manage” tab on the ribbon, then in the “Style & Standards” panel, click the “Linetype” dropdown and select “Other…”.
Within the Linetype Manager, click the “Load” button. This opens a dialog box listing all available linetypes in the AutoCAD linetype library (.lin file). Select the desired dashed linetype (e.g., DASHED, HIDDEN, PHANTOM) and click “OK” to load it into your current drawing. You can then select it as the current linetype to use when drawing.
Why does my dashed line appear as a solid line in AutoCAD?
One common reason for dashed lines appearing solid is an incorrect linetype scale (LTSCALE). If the LTSCALE is too small relative to the drawing units, the dashes and spaces become too small to be visible, effectively rendering the line as solid.
Another possible cause is that the object is simply too short. If the length of the line segment is shorter than the dash length of the selected linetype, the entire line will appear as a single dash, giving the illusion of a solid line. Try increasing the linetype scale or lengthening the line to see if this resolves the issue.
How do I change the linetype scale for dashed lines in AutoCAD?
You can change the linetype scale globally for the entire drawing or individually for selected objects. To adjust it globally, type “LTSCALE” in the command line, press Enter, and then enter a new scale factor. A larger number increases the size of the dashes and spaces, while a smaller number decreases them.
To modify the linetype scale for specific objects, select the objects you want to change. Then, in the Properties panel, locate the “Linetype Scale” property and enter the desired scale factor. This allows you to fine-tune the appearance of dashed lines on a per-object basis without affecting the entire drawing.
Can I create my own custom dashed linetypes in AutoCAD?
Yes, you can create custom dashed linetypes in AutoCAD to suit specific project requirements. This involves defining a linetype pattern that consists of a sequence of dashes, spaces, and optionally text or symbols. Custom linetypes are defined in a text-based linetype definition file (.lin).
To create a custom linetype, you can edit an existing .lin file or create a new one. The file requires a specific format, including a name, description, and a sequence of positive and negative values representing dashes and spaces respectively. Once defined, the custom linetype can be loaded into AutoCAD and used like any other standard linetype.
How do I ensure that dashed lines display correctly in paper space layouts?
Ensuring correct display of dashed lines in paper space layouts often requires adjusting the viewport linetype scale (VISCALE). This is because the linetype scale in model space might not translate well to the scaled-down representation in the layout.
To adjust the VISCALE, select the viewport and access its Properties panel. Locate the “Viewport Linetype Scale” property and adjust the value until the dashed lines appear appropriately scaled within the viewport. This ensures that the dashes and spaces are clearly visible and proportional to the rest of the drawing in the layout.
Why are the corners of my dashed lines not meeting properly in AutoCAD?
Improper alignment of dashed lines at corners often occurs when the linetype is not properly aligned or adjusted. AutoCAD provides the “PLINEGEN” system variable which controls how linetypes are generated around polylines. When PLINEGEN is set to 0, linetypes start at the beginning of each segment, potentially causing misalignments at corners.
Setting PLINEGEN to 1 forces the linetype to be generated continuously along the entire polyline length, ensuring that dashes and spaces maintain a consistent pattern even at corners. Type “PLINEGEN” in the command line, press Enter, and then set the value to 1 to correct this issue and achieve smoother, more consistent corner transitions with dashed lines.