Tutorials

How to create custom hatch patterns in AutoCAD? (Solved)

Introduction

Many AutoCAD users need custom hatch patterns to represent materials, finishes, or repetitive details not available in the default pattern library. This guide gives a clear, beginner‑friendly, and search‑optimized walkthrough to create, test, import, and troubleshoot custom hatch (.pat) patterns, plus alternative methods and practical tips.

Short answer (quick overview)

  • Create a plain‑text .pat file with the pattern definition, place it in AutoCAD’s Support File Search Path, then restart AutoCAD.
  • Use the HATCH command (or Hatch Creation ribbon) and select your custom pattern from the patterns list.
  • Adjust Scale, Angle, and Origin to get the correct appearance.

Full step‑by‑step tutorial

H2 Create a custom hatch pattern file (.pat)

  1. Open a plain text editor (Notepad on Windows).
  2. Start with a header line: begin with an asterisk, the pattern name, then a comma and a short description. Example:
    • MYBRICK, My brick pattern for elevations
  3. Add one or more pattern data lines. Each data line defines a family of parallel lines for the pattern. A typical line structure is:
    angle, x-origin, y-origin, delta-x, delta-y, dash1, dash2, …

    • angle — direction of the lines in degrees.
    • x-origin, y-origin — the origin point that anchors the pattern.
    • delta-x, delta-y — the repeat shift vector for the next parallel line family.
    • dash numbers — lengths that define dashes and gaps; a single 0 means a continuous line.
  4. Save the file with a .pat extension (for example, MyPatterns.pat).

Example: simple 45° diagonal hatch (based on common PAT syntax)

ANSIEXAMPLE, Simple diagonal 45° pattern
45, 0,0, 10,10, 0,-5

Explanation:

  • The header names the pattern (ANSIEXAMPLE).
  • The data line draws 45° lines, repeats every (10,10), and uses a continuous line segment (0) with spaces (-5) to create dashed effect. (Adjust numbers to control spacing and repeat.)

H2 Load the .pat file into AutoCAD

  1. Place your .pat file in a folder.
  2. Open AutoCAD. Go to Options > Files tab > Support File Search Path and either:
    • Add the folder containing your .pat file, or
    • Copy the .pat file into an existing support path (e.g., AutoCAD’s Support folder).
  3. Restart AutoCAD so it recognizes the new pattern file.

H2 Apply your custom hatch in a drawing

  1. Use the HATCH command or the Hatch Creation ribbon.
  2. In the pattern dropdown, find and select your custom pattern name (it appears alongside predefined patterns).
  3. Pick the hatch boundary (pick internal point(s) or select object).
  4. Adjust Scale and Angle in the Hatch dialog or Properties to match drawing units and desired density.
  5. Use Set Origin (HATCH command options or Hatch Editor) if pattern alignment must match other elements.

H2 Edit and refine a pattern

  • To change the pattern geometry, edit the .pat file (text editor), save changes, restart AutoCAD, and reapply the hatch.
  • Use different pattern lines in a single .pat file to combine multiple line families (for complicated patterns such as brick or cobble).

Alternative methods (no .pat required)

H3 1) Build a repeated pattern using blocks and arrays

  • Create a small repeating element as a block (for example, a brick motif).
  • Use ARRAY (rectangular or associative) to tile the block across your area.
  • Advantage: full graphic control (textures, fills, colors). Disadvantage: heavier drawing and not a true hatch (cannot use Hatch-specific properties).

H3 2) Use multiple hatch layers

  • Hatch the same area multiple times using different standard patterns, rotation, and scales to approximate a complex pattern.
  • Advantage: quick, uses built‑in patterns. Disadvantage: limited precision and may be slower to manage.

H3 3) Use third‑party pattern generators or libraries

  • Several websites and plugins generate .pat definitions from sample patterns or images.
  • You can download .pat files and import them the same way (add to Support File Search Path).
  • Always verify licensing when using third‑party patterns.

Common errors and fixes

H2 Pattern not showing up in the Hatch list

  • Fix: Ensure the .pat file is in a folder listed under Options > Files > Support File Search Path, then restart AutoCAD.

H2 Pattern looks too dense / too sparse

  • Fix: Change the Scale value in the Hatch dialog. Higher scale = larger spacing (lighter density), lower scale = tighter spacing (denser).

H2 Pattern orientation is wrong

  • Fix: Adjust the Angle in the Hatch dialog or use Set Origin to align the pattern correctly.

H2 Pattern appears broken, displaced, or repeats oddly

  • Fixes:
    • Check the delta-x/delta-y repeat vector values in the .pat data lines — they control how the pattern repeats.
    • Ensure you use a period (.) as a decimal separator (locale issues can cause parsing errors).
    • Confirm you used correct separators and no unexpected characters (use plain ASCII text).

H2 Pattern uses wrong units or scale

  • Fix: Consider whether your hatch is annotative. Turn annotative on/off depending on whether you want the pattern to scale automatically with viewport or stay fixed in model space.

Practical tips and best practices

  • Test patterns in a simple new drawing first (unit 1:1) to validate spacing and repeat before using them in a project.
  • Keep .pat files organized in a dedicated folder and add that folder once to the Support File Search Path — easier distribution and backups.
  • Use meaningful pattern names and descriptions in the header line to help team members identify patterns quickly.
  • For CAD standards, store common .pat files in a central network folder so all team members access the same patterns.
  • When creating patterns for printing, test at final print scale to verify visual results (paper space vs model space differences).

FAQ

How do I share custom hatch patterns with other team members?

Place the .pat file in a shared network folder, add that folder to each user’s Support File Search Path (Options > Files), and have users restart AutoCAD. Alternatively, provide the .pat file and instructions to copy it into their AutoCAD Support folder.

Can I convert an image (PNG/JPG) into a hatch pattern?

AutoCAD cannot directly convert raster images into native hatch patterns. Options:

  • Trace the image and create vector geometry, then make a block and array it as a tiling pattern.
  • Use third‑party tools or plugins that convert images to .pat definitions (results vary).

Why does my custom pattern scale differently in model space vs viewport?

If the hatch or the pattern is annotative, it will scale automatically with viewport scale. Turn off annotative for fixed pattern scale, or create annotate-appropriate patterns and use viewport scale handling.

Is there a limit to how complex a .pat pattern can be?

A .pat can include multiple line families to build complex patterns, but very complex patterns can be difficult to control and may be better implemented as a tiled block or image depending on performance needs.

Can I make my custom hatch pattern show up in the Hatch palette thumbnails?

AutoCAD generates thumbnails for many patterns automatically. If a pattern is complex or new, restart AutoCAD after placing the .pat file in the support path; sometimes thumbnails require a refresh. If thumbnails still do not show, the pattern is still usable by name — just select it from the list.

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