Hi ndrakey, you can use the locking function to make objects stay visible yet not be selectable. You can also set an option to make locked objects non-snappable in additional to non-selectable, to do that go to Options > Snap > "Object snap options"and uncheck "Snap to locked objects".

To lock objects, select them and then use Edit > Lock, or also in the Scene browser you can lock by using a Ctrl+click on the left-hand column where you usually see the eye icon, it will switch to a lock icon with a Ctrl+click.

It kind of sounds like you're trying to do some type of reverse engineering or object reconstruction though - MoI is not really designed to do that particular type of task or to deal with objects made up of a large number of flat facets like a polygon mesh modeler, so you may run into various difficulties.

- Michael