How to Use Carbon Copy in FreeCAD Sketcher

The Carbon Copy tool in FreeCAD allows you to duplicate the entire contents of an existing sketch—including geometry, constraints, and dimensions—directly into your active sketch. This guide provides a straightforward walkthrough on how to prepare your sketches, activate the tool, transfer geometry, and manage copied constraints to speed up your parametric modeling workflow.

Prerequisites

Before using the tool, ensure you have:

  1. A source sketch: An existing sketch containing the geometry and constraints you want to duplicate. Ensure this sketch is set to Visible in the Tree view (select it and press the Spacebar).
  2. A target sketch: An active sketch opened in Edit mode where the copied elements will be placed.

Step-by-Step Instructions

  1. Enter Edit Mode in the Target Sketch: Double-click the sketch you want to copy geometry into, or create a new sketch and remain in the Sketcher workbench.

  2. Activate the Carbon Copy Tool: Click the Create carbon copy icon in the Sketcher toolbar, or navigate to Sketch → Sketcher tools → Carbon copy from the top menu. The mouse cursor will change to indicate the tool is active.

  3. Select the Source Sketch: Click on any visible element or edge of the source sketch within the 3D viewport.

  4. Review the Transferred Elements: FreeCAD immediately transfers all lines, arcs, circles, and associated constraints from the source sketch to the active target sketch.

Managing Constraints and References

  • Standard Copy: By default, clicking the source sketch copies all geometry along with its original dimensional and geometric constraints.
  • Copying Without Constraints: If you only need the raw geometry without any constraints, hold the Ctrl key while clicking the source sketch in the 3D view.
  • Independence: The copied geometry is completely independent of the original sketch. Changes made to the original sketch after performing a carbon copy will not automatically update the copied geometry in the target sketch.
  • Repositioning: Because dimensions and datum constraints transfer over, you may need to delete external reference constraints (such as lock constraints to the origin) to move or reposition the copied geometry within the new sketch.