Creating Custom Hatch Patterns in AutoCAD for Mac

AutoCAD for Mac provides powerful tools for creating and applying hatch patterns to your drawings, but sometimes the built-in library isn’t enough. Whether you’re working on architectural details, landscape plans, or mechanical schematics, custom hatch patterns can help you communicate your design intent more clearly. This guide walks you through the process of creating and implementing your own hatch patterns in AutoCAD for Mac.

Understanding Hatch Patterns in AutoCAD

Hatch patterns in AutoCAD are defined using a simple text-based format stored in .pat files. These files contain instructions that tell AutoCAD how to draw lines, dots, or other shapes to fill an enclosed area. While Windows versions of AutoCAD store these files in a specific support folder, AutoCAD for Mac uses a slightly different file structure.

Step 1: Locate the Support Folder

Before you can add a custom hatch pattern, you need to know where AutoCAD for Mac stores its support files:

1. Open Finder.
2. Navigate to:
   ~/Library/Application Support/Autodesk/AutoCAD 20XX/Rxx.x/enu/Support/
   (Replace “20XX” and “Rxx.x” with your actual AutoCAD version number, e.g., “2024” and “R24.0”)
3. If the Library folder is hidden (which is common in macOS), press Command + Shift + G in Finder and type:
   ~/Library/Application Support/Autodesk/

Tip: You can also find the support path directly from AutoCAD:

• Type OPTIONS in the command line.
• Go to the Files tab.
• Expand Support File Search Path to see all directories AutoCAD checks for .pat files.

Step 2: Create a New .PAT File

You can either edit an existing .pat file or create a new one. For clarity and organization, it’s best to create a new file for your custom patterns.

1. Open TextEdit (or any plain-text editor like BBEdit or VS Code—avoid Word or Pages, as they add formatting).
2. Save the file with a .pat extension (e.g., MyCustomHatch.pat) in the Support folder identified above.
3. Make sure the file is saved as Plain Text (in TextEdit: Format > Make Plain Text).

Step 3: Define Your Hatch Pattern

Each hatch pattern begins with a header line that starts with an asterisk (*), followed by one or more definition lines.

Basic Syntax:

*PatternName, Description
Angle, X-origin, Y-origin, Delta-X, Delta-Y, [Dash1, Dash2, ...]

• PatternName: The name that appears in the Hatch dialog.
• Description: Optional descriptive text.
• Angle: Rotation angle of the line in degrees.
• X-origin, Y-origin: Starting point of the first line.
• Delta-X: Spacing between lines perpendicular to their direction.
• Delta-Y: Spacing along the line direction (usually 0 for simple line patterns).
• Dash lengths: Optional; positive = pen down (draw), negative = pen up (skip).

Example: Simple Diagonal Lines

*MyDiagonal, 45-degree diagonal lines
45, 0,0, 0,0.125

This creates lines at 45°, spaced 0.125 units apart.

Example: Brick Pattern

*BRICK, Brick bond pattern
0, 0,0, 0,0.5
90, 0,0, 0.5,0.5, -0.25,0.25

Note: All units are in drawing units. Use consistent scales based on your typical drawing setup.

Step 4: Save and Reload in AutoCAD

1. Save your .pat file.
2. Restart AutoCAD for Mac to ensure it recognizes the new pattern.
   • Alternatively, you can reload hatch patterns by typing -HATCH (with the hyphen) in the command line, then ? to list available patterns—this often forces a refresh.

Step 5: Apply Your Custom Hatch

1. Type HATCH in the command line.
2. In the Hatch Creation tab, click the Pattern drop-down.
3. Your custom pattern (e.g., “MyDiagonal”) should now appear in the list under User Defined or at the bottom of the pattern list.
4. Select it, adjust scale and angle as needed, and click inside a closed boundary to apply.

Tips for Success

• Test small: Start with simple line patterns before attempting complex shapes.
• Use consistent units: If your drawings are in millimeters, design your pattern accordingly.
• Backup your .pat files: Store copies outside the support folder to avoid losing them during updates.
• Combine patterns: You can define multiple patterns in a single .pat file—just separate each with its own * header line.

Troubleshooting

• Pattern doesn’t appear? Double-check the file location and ensure it’s plain text with a .pat extension.
• Hatch looks wrong? Verify spacing values and angles. Use the HATCHEDIT command to adjust scale after placement.
• AutoCAD crashes? Invalid syntax in .pat files can cause instability. Validate your pattern definition carefully.

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Frequently Asked Questions (FAQ)

Q1: Can I use Windows .pat files directly in AutoCAD for Mac?

A: Yes, in most cases. The hatch pattern syntax is identical between AutoCAD for Windows and Mac. You can copy a .pat file from a Windows installation and place it in the Mac support folder. However, ensure the file is saved in plain text format with Unix-style line endings (LF), as macOS may not interpret Windows line endings (CRLF) correctly in some edge cases.

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Q2: Do custom hatch patterns work in AutoCAD LT for Mac?

A: No. AutoCAD LT for Mac does not support user-defined hatch patterns. Only the standard built-in hatch libraries are available in LT versions. You need the full version of AutoCAD for Mac to load and use custom .pat files.

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Q3: Why doesn’t my custom hatch appear in the Hatch Pattern list even after restarting AutoCAD?

A: First, confirm the .pat file is in one of the folders listed under Support File Search Path (check via OPTIONS > Files tab). Second, ensure the file contains at least one valid pattern definition starting with *. Third, avoid using special characters (like accented letters or symbols) in the pattern name—stick to alphanumeric characters and underscores.

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Q4: Can I create solid-fill or bitmap-style hatches using .pat files?

A: No. The .pat format only supports vector-based line and dot patterns. Solid fills are handled by the SOLID hatch type, and image-based (bitmap) fills are not supported through .pat files in AutoCAD. For complex textures, consider using a raster image with transparency or a block-based fill workaround.

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Q5: How can I share my custom hatch pattern with a colleague using AutoCAD for Mac?

A: Simply send them your .pat file. They should place it in their own AutoCAD for Mac Support folder (located at ~/Library/Application Support/Autodesk/AutoCAD [version]/.../Support/) and restart the application. For team consistency, consider storing shared .pat files in a common network location and adding that path to everyone’s Support File Search Path.

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Q6: Is there a way to preview my custom hatch pattern before applying it?

A: AutoCAD for Mac doesn’t offer a live preview of custom .pat patterns in the Hatch dialog like some Windows versions do. However, you can create a small test rectangle, apply the hatch at your intended scale, and adjust as needed. Alternatively, use the -HATCH command (with a hyphen) and type ? to list all available patterns—this confirms your pattern is loaded correctly.

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Q7: Can I edit a built-in hatch pattern like ANSI31 or AR-CONC?

A: You shouldn’t edit AutoCAD’s default .pat files (e.g., acad.pat), as updates may overwrite them. Instead, copy the pattern definition into your own custom .pat file, rename it (e.g., MY-AR-CONC), and modify the values there. This preserves the original while giving you a safe, editable version.

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Conclusion

Creating custom hatch patterns in AutoCAD for Mac gives you greater control over your documentation and presentation. While the process requires editing text files and understanding basic pattern syntax, the results are well worth the effort—especially for industry-specific or company-standard fills. With this guide, you’re ready to design hatches that perfectly match your project needs.