AutoCAD LT supplies a solid fill and more than 50 industry-standard hatch patterns, which can represent materials such as earth, brick, or clay. Fourteen hatch patterns conform to International Standards Organization (ISO) standards. These patterns are at the end of the pattern list in the Boundary Hatch dialog box. When you select an ISO pattern, you can specify a pen width, which determines the line weight in the pattern. In addition to the patterns supplied with AutoCAD LT, you can use patterns from an external pattern library. These patterns are also listed by name and displayed in the Hatch Pattern Palette dialog box.
You can define a simple line pattern using the current linetype with the User-Defined Pattern option, or you can create more complex hatch patterns. To reduce file size, a hatch pattern is defined in the drawing database as a single graphic object.
The hatch patterns supplied by AutoCAD LT are stored in the ASCII text file aclt.pat. You can add pattern definitions to this file or create your own files.
The Pattern area of the Boundary Hatch dialog box displays the names of all the hatch patterns defined in the aclt.pat text file. You can add new hatch patterns to the dialog box by adding their definitions to the aclt.pat file.
Creating Solid-Filled Areas
Customizing Hatch Patterns
Using Hatch Pattern Definition Files