From FreeCAD Documentation
- Optionally change the working plane.
- Make sure snapping is enabled. See Draft Snap Lock.
- If Draft Snap WorkingPlane is not active do one of the following:
- Press the button in the Draft snap toolbar.
- Press the button in the Draft snap widget.
- Make sure at least one other snap option is active.
- Choose a Draft or Arch command to create your geometry.
- Note that you can also change snap options while a command is active.
- Move the cursor over the object you want to snap to.
- The object is highlighted.
- If a snap point is found it is projected onto the working plane where it is marked.
- Click to confirm the point.