Hatch pattern files (.pat) are just ordinary text files consisting mainly of numbers, which is the code AutoCAD uses to draw the hatches. The patterns in both files are the same except for the dimensions used. acad.pat contains the hatch patterns used in imperial drawings, and acadiso.pat contains the hatch patterns used in metric drawings. The standard AutoCAD hatch files are acad.pat and acadiso.pat (aclt.pat and acltiso.pat for LT). You need to locate your existing two standard AutoCAD (or LT) hatch files, open them in a text editor, then copy the hatch pattern code from my file (hatch_pattern_code.txt) into them. You will then see the new hatch patterns alongside the standard AutoCAD patterns in the 'Other Predefined' tab when using the BHATCH command. Make sure there is a carriage return at the end of the last line. For newer versions of AutoCAD please use this tutorial for help with installing hatch patternsįor AutoCAD 2009, 2008, 2007, 2006, 2005, 2004 LT 2009, 2008, 2007, 2006, 2005, 2004Ĭopy and paste the entire contents of my file hatch_pattern_code.txt into your acad.pat hatch file and your acadiso.pat hatch file (aclt.pat and acltiso.pat hatch files for LT).