Curtain wall units are subunits of geometrically complex curtain walls, which often have a large number of different elements, like frames, panels, and infills. Most of these settings are defined in the style. However, there are cases when modifying a curtain wall unit directly on screen is more suitable:
When you have finished your onscreen edits, you can decide if you want to
Overrides you can set include assigning a different definition to a selected cell, frame, or mullion, and assigning a profile to a frame or mullion edge. Note that the definition or profile must already exist in the current drawing before you can use it as an override.
Overrides do not affect the Design Rules for the curtain wall unit style. However, you can transfer overrides to a curtain wall unit style if you want all curtain wall units of that style to have the same overrides.
You can view a list of overrides that are currently assigned to a curtain wall unit from the Overrides tab of the Curtain Wall Unit Properties dialog box.