Hi Brian,

> I have not located a script which adds geometry, then does user picks, with Cancel not
> causing added geometry to remain.

There should be a lot of the default commands that would be examples of this, for example if you push Cancel in the Line command instead of finishing the second point pick it won't leave behind whatever line was showing.


> I used .clone to reveal the top and bottom edges of the frustum, rather than a factory...

That's ok, but yes if you are not using the factory update()/commit() mechanism it will be up to the script to do the cleanup, it won't happen automatically.

- Michael