Hi s7r83dg3, hiding the outside object like mentioned above is a good way.

But there are also a couple of other ways to select the object inside another one as well.

Ctrl+A for "Select All" (or use the Sel All button under the Select palette on the side pane), or invert selection will do it. You can use these selection options at pretty much any select objects prompt.


But probably even easier than that is to just use a window select to capture the inside objects. Just click the mouse down on an empty area and hold down and drag, and you will get a selection box that captures stuff inside of it. For example here I use it to capture a box that is contained inside of a sphere:



Also check out this previous example:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1810.2


After you have selected the first object in boolean difference, it will be screened out from selection so you can actually start the window on that first object without a problem. But in other situations like when you are in selection mode before running a command, sometimes it can be difficult to find an empty area to click in to start the window select. When that happens you can solve it by holding down Ctrl+Shift before clicking, that forces window selection instead of trying to drag the object that you may be initially clicking on.

Also, the side that you start for the window selection can be significant - if you start on the left and drag towards the right, the window will have a solid outline and only objects that are completely contained inside of it will be targeted. If you start on the right and drag towards the left, the window will have a dashed outline and any object that intersects the window even partially will be targeted. Often times one of these can be helpful for particular selection tasks.

- Michael