Pathstitch

Pathstitch is a 2D drafting tool for cutting patterns and templates for leather and sewing. You draw lines, circles, polygons and pen curves with snapping and live dimensions, round corners parametrically, trim and combine closed shapes, and place saddle-stitch holes along a path. It exports DXF, SVG, PDF and PNG. It can also import STEP models and unfold developable surfaces into flat panels. It is for makers who want precise flat patterns without a full CAD suite.

It requires an Apple silicon Mac on macOS 14 or later, and the README says there is no Intel build. The download is ad-hoc signed and not notarized, so the first launch has to be approved under Privacy & Security in System Settings; the README gives the steps. The README describes the 2D tools as mature and the 3D unfolding as limited to developable surfaces and still expanding. The license is GPL-3.0, and the README notes that it bundles Potrace, which is also GPL.