What Is Pat File in AutoCAD?

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In AutoCAD, a PAT file is a pattern definition file that specifies the fill pattern used for hatches and fills in drawings. It determines how the area enclosed by an object or boundary is filled with lines, dots, or other shapes.

What Is a Fill Pattern?

A fill pattern is a combination of lines and shapes that are repeated in a defined order to cover an area. It is used to represent various materials or textures in drawings, such as bricks, tiles, grass, sand, etc.

Creating PAT Files

To create a custom PAT file or modify an existing one in AutoCAD:

  • Step 1: Open the Hatch and Gradient dialog box by typing “HATCH” on the command line or selecting it from the Ribbon menu.
  • Step 2: In the dialog box, click on the “Pattern” button to open the Select Hatch Pattern dialog box.
  • Step 3: In the Select Hatch Pattern dialog box, click on the “Custom” tab to access custom patterns.
  • Step 4: Click on the “Import..” button to import an existing PAT file or click on the “New.” button to create a new one.

PAT File Format

A PAT file consists of multiple pattern definitions. Each definition starts with a line containing its name enclosed within asterisks (*).

The subsequent lines specify the pattern using characters such as dots (. ), dashes (-), and spaces ( ).

The most commonly used characters are:

  • .: Represents a dot-shaped element
  • –: Represents a line element
  • : Represents an empty or transparent space

The order and combination of these characters determine the appearance of the fill pattern.

Using PAT Files

To use a custom PAT file for hatching or filling an area in AutoCAD:

  • Step 1: Open the Hatch and Gradient dialog box.
  • Step 4: Select the desired pattern from the list.

Note:

In addition to using custom PAT files, AutoCAD provides a variety of predefined hatch patterns that can be used as well. These patterns are stored in a separate file called ‘acad.pat’ which is located in the support directory of your AutoCAD installation.

In Conclusion

A PAT file is a crucial component when it comes to creating visually appealing drawings in AutoCAD. By defining fill patterns, you can effectively represent various materials and textures in your designs. With a thorough understanding of how to create, format, and use PAT files, you can enhance your drawings with customized hatches and fills.