PartDesign Fillet

Description
The PartDesign Fillet tool creates fillets (rounds) on the selected edges of an object. It adds a Fillet object to the document with its corresponding representation in the Tree view.

Add a fillet

 * 1) Optionally activate the Body to fillet.
 * 2) There are several ways to select edges to fillet:
 * 3) * Select one or more edges of the Body individually.
 * 4) * Select one or more faces of the Body to select all their edges.
 * 5) * Select a feature (usually the last feature) of the Body to select all its edges.
 * 6) For a chain of tangentially connected edges only a single edge needs to be selected, the fillet will propagate along the chain.
 * 7) There are several ways to invoke the tool:
 * 8) * Press the button.
 * 9) * Select the option from the menu.
 * 10) If there is no active Body, and there are two or more Bodies in the document, the  dialog will open and prompt you to activate one. If there is a single Body it will be activated automatically.
 * 11) The  task panel opens. See Options for more information.
 * 12) Press the  button to finish.

Edit a fillet

 * 1) Do one of the following:
 * 2) * Double-click the Fillet object in the Tree view
 * 3) * Right-click the Fillet object in the Tree view and select from the context menu.
 * 4) The  task panel opens.See Options for more information.
 * 5) Press the  button to finish.

Options

 * To add edges do one of the following:
 * Press the button to start selecting edges and/or faces in the 3D view.
 * To select all remaining edges do the following:
 * If required press the button.
 * Use the ++ keyboard shortcut, or right-click the list and select from the context menu.
 * To remove edges do one of the following:
 * Press the button to start deselecting edges and/or faces in the 3D view. Selected elements are highlighted in purple.
 * Select one or more elements in the list and press the key, or right-click the list and select  from the context menu.
 * Set the of the fillet.
 * Check the checkbox to select all edges of the previous feature. This deactivates the selection list and the related buttons.

Properties
See also: Property editor.

A PartDesign Fillet object is derived from a Part Feature object and inherits all its properties. It also has the following additional properties:

Data

 * : Link to the selected edges and faces of the parent feature. Can be a link to only the parent feature if is.
 * : If the filleted shape of the additive/subtractive parent feature will be used when the fillet object is included in a pattern, else only the shape of the fillet itself will be used. The default is.
 * : Link to the parent feature.
 * : Link to the parent body.
 * : Link to the parent body.


 * : The fillet radius. The default is.
 * : If all edges of the feature are filleted, and the edges specified by  are ignored. The default is.


 * : If redundant edges are removed from the result of the operation. The default value is determined by the  preference. See PartDesign Preferences.

Known issues
Fillets, chamfers, and other features that operate on solid bodies depend on the underlying OpenCASCADE Technology (OCCT) kernel that FreeCAD uses. The OCCT kernel occasionally has difficulty handling coincident sharp edges, where two faces meet. If this is the case FreeCAD may crash without an explanation.

If run from the terminal, FreeCAD may output a log like this after a crash:

This output references functions from OCCT libraries. If this type of crash occurs, the problem may need to be reported and solved in OCCT rather than in FreeCAD.

See the forum threads for more information:
 * Bug Chamfer bigger than 2mm crashes freecad
 * Segfault when using part design fillet

Topological naming
Edge numbers are not completely stable, therefore it is advisable that you finish the main design work of your solid body before applying features like fillets and chamfers, otherwise edges could change names and filleted edges would likely become invalid. When the property  is  there is some protection from this. Because in such cases all the edges of the base object are used and there is no dependence on individual edge names.

Read more in topological naming problem.