# PDF Underlay Command [GstarCAD 2021](Help%20System/GSTARCAD/2021/Index.md) → [Commands](Help%20System/GSTARCAD/2021/Commands/(Commands).md) → [P](Help%20System/GSTARCAD/2021/Commands/P/(P).md) ## PDF Underlay **Menu:** Insert\>Reference\>PDF Underlay **Command Entry:**PDFATTACH If you receive project drawings in the form of a PDF file, you can reuse that PDF data in your own GstarCAD drawing files. For example, imagine that you are a landscape designer and you receive a PDF file for this building project. This particular sheet includes a floor plan that you want to use as starting point for your landscape design. --- Gstarsoft Co.,Ltd