From FreeCAD Documentation
- Make sure snapping is enabled. See Draft Snap Lock.
- If Draft Snap Ortho is not active do one of the following:
- Press the button in the Draft snap toolbar.
- Press the button in the Draft snap widget.
- Choose a Draft or Arch command to create your geometry.
- Note that you can also change snap options while a command is active.
- Pick a first point. This snap option requires a previous point.
- If you move the cursor around the previous point you will notice a "magnetic" effect when the cursor is on an imaginary infinite line crossing that point at an angle of 0°, 45°, 90° or 135°.
- The point is marked and the icon is displayed near the cursor.
- Click to confirm the point.