To open the Tools window for Replace Faces, from the Geometry toolbar, Defeaturing and Repair () menu, select Replace Faces (). You can also right-click the Geometry node and select the same option from the context menu.

Select the faces you want to replace in the Graphics window. They appear in the Faces to replace list.

In the Heal method list, select the method to use for covering the wounds after deleting the faces to be replaced: Create capping faces means that new faces are generated based on the edges surrounding each wound, while Extend adjacent faces means that the adjacent faces are grown or shrunk to heal the wounds. Select the Heal as through hole check box if you have selected faces that make up a hole that you want to delete and replace.

When you click the Replace Selected button, the program deletes and replaces the selected faces and adds a node corresponding to this operation to the geometry branch of the model tree. The Tools window for Replace Faces remains open so that you can continue defeaturing using this or another defeaturing tool.

If you want to modify the performed replace operation, select the added node in the geometry branch. Then edit the node’s form that appears in the Settings window. Click the Build Selected button () to see the result of your edits. The Settings window for Replace Faces contains the additional settings described below.

If you want to make the resulting entities contribute to a cumulative selection, select a cumulative selection from the Contribute to list (the default, None, gives no contribution), or click the New button to create a new cumulative selection (see Cumulative Selections in the COMSOL Multiphysics Reference Manual).

Select the Resulting objects selection check box to create predefined selections (for all levels — objects, domains, boundaries, edges, and points — that are applicable) in subsequent nodes in the geometry sequence. To also make all or one of the types of resulting entities (domains, boundaries, edges, and points) that the resulting objects consist of available as selections in all applicable selection lists (in physics and materials settings, for example), choose an option from the Show in physics list: All levels, Domain selection, Boundary selection, Edge selection, or Point selection. The default is Domain selection, which is suitable for use with materials and physics defined in domains. For use with a boundary condition, for example, choose Boundary selection. These selections do not appear as separate selection nodes in the model tree. Select Off to not make any selection available outside of the geometry sequence.