De-unionizing a unionized model

Is it possible to reverse the union placed on a model so I can edit or delete pieces of the model? Or is the union function permanent? Just curious.

It will be. It is in the History Based Parametric Modeling (HBPM) version that is currently in beta and open to everyone to try.

In the current release version, you’re limited to the undo function and the union becomes permanent once you exit the project. As Bob mentioned, the beta allows you to undo any operation at any time, with the potential consequences of affecting other subsequent operations. The one exception to this rule is sketches: you cannot undo a sketch change in history in the present beta.

I see. Undoing the sketch might cause havoc to the structure of the model.

Plus, if history recorded every line and curve on a sketch, it would make the history list unwieldy.