AutoCAD has a built-in tool called (often part of the Express Tools). It allows you to use an image or a block as a hatch pattern.

Here’s an interesting and useful breakdown for anyone looking to convert files into PAT (hatch pattern) files—something that’s notoriously tricky because PAT files are plain text definitions, not direct vector exports.

A high-quality converter—whether it is a standalone executable or an AutoCAD "LISP" routine—distinguishes itself through three main pillars: precision, automation, and optimization.

A better converter reads the $MEASUREMENT and INSUNITS variables from the DWG.

| If you want… | Best solution | |--------------|----------------| | | BricsCAD (trial) or AutoCAD + LISP | | Turn drawn lines into a new PAT | HatchKit (paid) – unbeatable quality | | Free + no software install | Web: dwg2pat (rare, mostly broken) – not reliable | | Automate many DWG files | Python + ezdxf (script yourself) |

If you are looking for a , it usually means you are facing one of these three hurdles: