Using Draft Upgrade and Downgrade in FreeCAD

This guide explains how to use the Draft Upgrade and Draft Downgrade tools in FreeCAD to convert, join, split, and simplify 2D and 3D geometry. You will learn the purpose of each tool, where to locate them, and how to apply them progressively to transform edges, wires, faces, and solids.

Understanding Upgrade and Downgrade

The Draft Upgrade and Draft Downgrade tools operate in opposite directions along an object hierarchy. Instead of performing a single fixed action, both tools change their behavior depending on the type and state of the selected geometry:

  • Draft Upgrade: Promotes geometry to a higher topological state (e.g., joining separate lines into a continuous wire, turning a closed wire into a face, or turning multiple faces into a solid).
  • Draft Downgrade: Demotes geometry to a lower topological state (e.g., breaking a 3D solid into separate faces, turning a face into wire boundaries, or splitting a wire into individual edges).

How to Access the Tools

  1. Open FreeCAD and switch to the Draft Workbench via the workbench dropdown.
  2. Ensure you have the geometry you want to modify visible in the 3D view.
  3. Locate the tools:
    • Upgrade: Click the Upgrade icon (upward-pointing arrow) on the Draft toolbar, press U then P on your keyboard, or go to Modification → Upgrade.
    • Downgrade: Click the Downgrade icon (downward-pointing arrow) on the Draft toolbar, press D then N on your keyboard, or go to Modification → Downgrade.

Step-by-Step: Using Draft Upgrade

The Upgrade tool moves geometry up the complexity ladder. If an operation does not fully reach the final desired shape on the first try, applying the tool a second or third time often moves it to the next level.

  1. Select the elements: In the 3D view or the Tree view, select the elements you want to combine or upgrade (for example, two or more touching lines).
  2. Execute Upgrade: Click the Upgrade button or use the shortcut U, P.
  3. Hierarchy progression:
    • Individual lines/arcs with shared endpoints merge into an open or closed Wire.
    • A closed wire becomes a Face.
    • Multiple overlapping faces or coplanar shapes merge via a Union.
    • A closed shell of faces can become a Solid.

Note: For separate edges to form a closed wire, their endpoints must meet precisely. If lines do not join, verify that snapping was used to share exact vertex coordinates.

Step-by-Step: Using Draft Downgrade

The Downgrade tool is used to deconstruct compound shapes or extract editable boundaries from higher-level objects.

  1. Select the element: Choose the object you want to decompose in the 3D view or the Tree view (for example, a solid box, a face, or a polyline).
  2. Execute Downgrade: Click the Downgrade button or use the shortcut D, N.
  3. Hierarchy progression:
    • A Solid or Compound breaks down into its individual Faces.
    • A Face converts into its perimeter Closed Wire.
    • A Closed Wire can be broken into an open wire or split into Individual Edges.
    • A Draft Block or clone expands back into its base elements.

Common Use Cases

  • Preparing 2D profiles for extrusion: If an imported DXF file consists of loose line segments, select them and apply Draft Upgrade once to create a wire, and a second time to create a face suitable for the Part or Part Design workbenches.
  • Extracting paths from 3D models: Select a face on a 3D solid and run Draft Downgrade to extract its border wires for use as sweep paths or toolpaths.
  • Fixing self-intersecting profiles: If an extrusion fails due to an invalid wire, run Draft Downgrade to break the wire into basic lines, adjust the faulty segments, and use Draft Upgrade to rebuild the profile.