How to Reorder Features in FreeCAD Part Design

Reordering features in the FreeCAD Part Design workbench allows you to modify the parametric history of your 3D model without having to delete and recreate operations. Because Part Design relies on a strict linear dependency tree, features can be rearranged using drag-and-drop actions or by manipulating the "Tip" of the active Body, provided that no parent-child dependency conflicts are introduced. This guide covers how to reorder features directly in the tree view, insert new features into an existing history, and troubleshoot common dependency errors.

Understanding the Sequential History

The Part Design workbench uses a cumulative, linear modeling approach. Each feature (such as a Pad, Pocket, or Fillet) depends on the cumulative solid created by the operations before it. Consequently, you cannot move a child feature before its parent geometry. For instance, a Pocket attached to the face of a specific Pad cannot be placed before that Pad in the tree view.

Method 1: Drag and Drop in the Model Tree

In modern versions of FreeCAD (0.20 and later), simple reordering can be performed directly within the tree view:

  1. Expand the active Body in the Model tree panel on the left side of the screen.
  2. Click and hold the feature you want to move.
  3. Drag the feature over the target feature you want to place it next to.
  4. Release the mouse button. The feature will shift to its new sequential position.
  5. If the model does not update immediately, press F5 to recompute the document.

Note: If the cursor displays a "prohibited" or "no" icon, the drop location violates a geometric dependency.

Method 2: Inserting Features by Changing the Tip

If you need to insert a new feature into the middle of your model history rather than moving an existing one, you can temporarily change the "Tip" of the body:

  1. Right-click the feature in the tree that should immediately precede your new operation.
  2. Select Set tip from the context menu. The model view will roll back to that state, temporarily hiding all subsequent operations.
  3. Create your new sketch or additive/subtractive feature. FreeCAD will insert it immediately after the current Tip.
  4. Once completed, scroll to the bottom of the Body, right-click the final feature in the tree, and select Set tip to restore the full model.
  5. Press F5 to recompute.

Troubleshooting Reordering Errors

Reordering often causes the model tree to display red or yellow warning icons. These usually indicate broken topological references:

  • Cyclic Dependency Errors: Occurs when Feature A relies on Feature B, but Feature B is moved before Feature A. Revert the move using Ctrl + Z and inspect the external geometry references in your sketches.
  • Missing Support Faces: If a sketch was mapped directly to a planar face created by an operation that now occurs later in the tree, the sketch will break. To fix this, select the sketch, open the Map Mode property in the Data tab, and re-link it to a valid plane or feature created earlier in the sequence.

Best Practices to Allow Easy Reordering

  • Reference Datum Planes: Whenever possible, attach sketches to default planes (XY, XZ, YZ) or Datum Planes rather than model faces. This detaches the sketches from downstream geometry and makes features freely movable.
  • Keep Dress-Up Features at the End: Operations like Fillets, Chamfers, and Drafts change face and edge indices. Keep these at the very bottom of the Part Design tree so they do not disrupt the references of core structural features.