We can use the tools to store and use positions for this.
- Make sure that QCAD stores each node for polylines when using the Misc > Information > Store Positions tool. Under Edit > Application Preferences > Info > Store Positions > Polylines, check “Store Nodes”.
- Select the polyline
- Misc > Information > Store Positions
- Start the spline tool: Draw > Spline > Spline (Fit Points)
- Apply the positions: Misc > Information > Use Positions
- Check the option Closed (Periodic) in the options tool bar at the top to create a closed, or uncheck the option to create an open spline:
- Terminate the spline tool with a click of your right mouse button or by hitting the Escape key on your keyboard.
