In IRONCAD, you can edit parts without history, such as those imported from STEP or ACIS files.
Procedure:
[1] Switch the Selection Filter to [Faces by auto-feature].
[2] Select the face(s) you want to delete from the imported geometry.
(Tip: Hold down the [Shift] key to select multiple faces.)
[3] Right-click on the selected face(s), and choose [Delete Faces] or [Delete Faces Directly] from the context menu.

[4] The Property Browser will automatically switch to [Delete Face Feature].
Click [OK] (green check mark) to confirm.


Depending on the condition and geometry of the data, it may also be possible to select and delete hole surfaces.