From FreeCAD Documentation
- Make sure you are in the edit mode of an existing sketch. This sketch is the target of the operation.
- There are several ways to invoke the tool:
- Press the Create carbon copy button.
- Select the Sketcher → Sketcher geometries → Create carbon copy option from the menu.
- Use the keyboard shortcut: G then W.
- The cursor changes to a cross with the tool icon.
- Pick an edge from another sketch. This sketch is the source of the operation. See Notes.
- Geometry elements as well as constraints are copied into the active sketch.
- This tool always runs in continue mode: optionally copy additional sketches.
- To finish, right-click or press Esc, or start another geometry or constraint creation tool.