The acad.pat (pattern / hatch) is a text file in AutoCAD that contains the source code for your hatch patterns. This PAT file is loaded every time you open a drawing in AutoCAD, and is used to set the default hatch patterns available in AutoCAD.
The path to your hatch pattern definitions can be found in the Support folder in AutoCAD. In this path there is a acad.pat file.
The problem may arise when you have multiple installations of AutoCAD you may have more than one .pat file. Here’s a quick tip on how to locate your AutoCAD Hatch Patterns and then set the path.
How to locate the .pat file
The first step in locating your AutoCAD hatch pattern (.pat) file is to search for it within Windows. You can do this by opening the File Explorer (press Ctrl E), then proceed by clicking on the “This PC” in the left window pane, and typing in the keyword “acad.pat” into the top box in upper right and press Enter.
This search should bring up any instance of all the available PAT files. Once the search is completed, right click on each pat file found you’ll have the option to choose Open File Location (or the folder where it resides). Then in the top you can right click and copy the folder location(s) to a text file.
Typical locations are where %USERNAME% is your name and xx.x is the version. These will vary depending on your machine and version of AutoCAD.
C:\Users\%USERNAME%\AppData\Roaming\Autodesk\AutoCAD LT 20xx\Rxx.x\enu\Support\acadlt.pat
This .PAT file can also be located in program files under your program files autocad-version support folder.
The Support File Search Path
Once you have located your .pat file folder location, you will need to type OP for Options. Click on the “Support File Search Path” tab. This will bring up a dialog box containing all of the paths AutoCAD looks in for various files.
Your active Pat file folder location should be placed near the top of this list. If it’s not you’ll need to choose Add then Browse the the folder you had copied from the search. Once the path is added, select Move Up to move it to the top. This will prioritize how AutoCAD will find it. Then click Apply followed by Ok button.
Test the path by typing HATCH command. If the hatches are still not showing correctly restart AutoCAD and test again. Also recheck path location.
If you make any changes to the Hatch codes within AutoCAD will be stored, it’s important that you always use this location when making modifications or adding new Hatch Patterns in order to avoid any conflicts or errors later down the line.
The video below covers how to find this path and open the .pat file. Our AutoCAD Hatch Patterns are used as an example.
In older versions of AutoCAD, hatches were stored in a folder called datacache. This folder was hidden and located in the same directory as the AutoCAD program files.
So you may find your Hatch Patterns are located in the UserDataCache folder.
This is a hidden folder and cannot be seen without changing your settings.
1. Open File Explorer (Windows+E)
2. Click on the View tab in the File Explorer window.
3. Check the box next to “Hidden items” in the Show/hide section of the ribbon.
4. Hidden folders and files will now be visible in File Explorer.
Once you find the acad.pat (or acadlt.pat) – make note of the path like describe above and add it to you path – type OP for options – then move to top to prioritize it as explained.
See also our Wood /Stone AutoCAD Hatch Patterns product