Hi Max,

> But still I have to select by hand all the objects to delete.

It should just be one window selection in the plan view...


> The problem is that this method is geometry-destructive, I mean that I always have to make a
> copy of the model or the file before doing it.

Why is that? You can just do something like open the file, do the operations you need, close the file and push "Discard changes" when it asks you if you want to save changes or not.

If you are super concerned about accidentally hitting save and overwriting the file, you can right-click on the Open button instead of left click. The right click does an "Open Template" instead of a plain open, and that does not set the current filename so it will prompt you for a filename if you hit Save that way.

- Michael