How to Offset a Wire or Curve in FreeCAD Draft

This guide provides a straightforward walkthrough on using the Offset tool within the FreeCAD Draft workbench to create parallel, expanded, or contracted variations of 2D wires and curves. You will learn the exact steps to select your geometry, activate the tool, set precise offset distances, and utilize modifier keys for non-destructive operations.

Step 1: Switch to the Draft Workbench

Open your project in FreeCAD and select the Draft Workbench from the workbench dropdown menu in the top toolbar.

Step 2: Select the Target Geometry

In the 3D view or the Tree view, click on the 2D wire, curve, or sketch you wish to offset. Ensure the selected object is planar, as the Draft Offset tool operates along the active working plane or the object's local plane.

Step 3: Activate the Draft Offset Tool

With the geometry selected, launch the tool using one of the following methods:

  • Click the Offset button in the Draft toolbar (represented by an icon showing concentric curved lines).
  • Use the keyboard shortcut: press O, then S.
  • Navigate to the top menu and select Draft → Offset.

Step 4: Set the Offset Distance and Direction

Once the tool is active, FreeCAD enters interactive placement mode:

  1. Interactive Method: Move your cursor across the 3D viewport. You will see a live preview of the offset wire expanding outward or shrinking inward relative to your cursor position. Click to set the position.
  2. Parametric Method: In the Draft parameters task panel on the left, type a precise numerical value into the Distance field and press Enter.

Useful Modifier Keys and Tool Settings

While the Offset tool is active, the task panel offers several settings to modify the behavior:

  • Copy mode (Alt key): By default, the offset command moves the original geometry. Check the Copy box (or hold the Alt key while clicking) to keep the original wire and generate a separate offset copy.
  • OCC Style: Toggle this option to switch between native Draft offset calculations and OpenCASCADE-based offsets, which often produce cleaner results on complex curves and rounded corners.
  • Reverse direction: Enter a negative numerical value or reposition your cursor on the opposite side of the wire to switch between an internal and external offset.

Modifying the Offset Later

If you created the offset in Copy mode, the resulting object appears as a Draft Offset feature in the Tree view. You can adjust the offset distance at any time by selecting the object, going to the Data tab in the Property View, and editing the Distance property.