Creating Hatch Patterns for AutoCAD

The “acad.pat” file contains the predefined hatching patterns used by AutoCAD. This file may be edited to add hatch patterns, supplemented, or replaced. All patterns start at the point 0,0, the pattern is calculated out to cover the hatching boundary.

Pattern definitions consist of the following fields:

A leading ‘*’

A name. The name can have no spaces, punctuation marks, parenthesis, or slashes.

A description

The standard format for hatch patterns is

<*><name><, description>

The name and the description are separated by a coma.

Descriptions cannot exceed the eighty character line length

After the introduction, the subsequent lines define the hatch pattern with the format of:

Angle, X-orgin, Y-orgin, delta-X, delta-Y, [definition string]

The definition string consists of varying length dashes denoted by positive numbers, spaces denoted by negative numbers and dots denoted by “0”’s. There is a maximum of six string definitions per line. All fields are comma delimited and terminated with a carriage return.

An example

* square, a square pattern

0, 0,0, 0,1, 1,-1

90, 0,1, 0,1, 1,-1

or, a second example

*pgram, parallelogram pattern

0, 0,0, 1,1, 1,-1

45, 0,0, 0,1.4142, 1.4142,-1.4142

45, 0,1, 0,1.4142, 1.4142,-1.4142

How to use the newly created pattern

Each pattern is created in its own file. The file name must have the same as the pattern name. The file extension for hatch pattern is xx.pat

After writing each line of code, the pattern should be loaded and checked to make sure that it is performing as expected. Corrections of multi-lined code become difficult and confusing.

To load custom designed Hatch patterns

From the TOOLS pull-down menu, click Design Center.

On the DesignCenter toolbar, at the top of the dialog box, click Search.

In the Search dialog box, click the drop down arrow of the Look For box.

Choose the Hatch Pattern Files.

If known, change the directory to the specific location of the file,

or BROWSE for the Drive and sub-directories

On the Hatch Pattern Files tab, in the Search for the Name box, enter *.

Pick “Search Now” to find the file.

When the search doesn’t find that pattern file. You know that pattern file is there. The search didn’t find the file. You’re sure that that pattern file is in the directory specified. The search still didn’t find the file. How come the search doesn’t find the pattern file?

HiNT: enter the file name as <first letter of the file name> and then an “*” i.e. e* for the pattern name “earth”.

By Double-clicking on the appropriate hatch pattern file, the HATCH command will be called and the chosen pattern will be loaded and ready to use.