Converting a DWG (AutoCAD Drawing) to a PAT (AutoCAD Hatch Pattern) file is a common challenge for designers who want to turn custom linework into reusable textures. Since AutoCAD doesn’t have a native "Save As PAT" button, you need a workflow to bridge the gap.
. While a DWG contains complex geometry, a PAT file is a simplified text-based instruction set that tells AutoCAD how to repeat a specific pattern. Autodesk Community, Autodesk Forums, Autodesk Forum Depending on whether you are trying to a pattern from an existing drawing or convert dwg to pat file
| Problem | Solution |
| :--- | :--- |
| Pattern is not seamless | Your DWG tile must be perfectly clipped to a rectangle. Use RECTANG + TRIM (Extend/Trim edges). |
| Lines are 3D or curved | PAT files only support straight lines. Use FLATTEN (2D) and _DONUT (convert arcs to short line segments). |
| File does not load in AutoCAD | PAT files must be plain text (Notepad), not Rich Text. Save as "All Files ." not .txt. |
| Pattern scale is wrong | PAT defines tile size in drawing units. If tile is 10mm in DWG, it will be 10mm in PAT. No scale metadata. | Converting a DWG (AutoCAD Drawing) to a PAT
Common Issues and Troubleshooting