With Alibre, etc, or an unwritten complex nurbs program: :-)

http://50.56.177.237/forum/index.php?webtag=MOI&msg=5549.2

Hi Marco, yes like Brian writes above there is not currently any way to get this data directly from MoI. I do plan on adding that in but for now you need to export your object to a different CAD program to get that information.

You can also export to STL format and there are various STL display/inspection programs that you can use which usually have volume calculations with them, here's one:
http://software.materialise.com/minimagics

- Michael

Minimagics works, but if you want something that is also free and can do some repairs to files you can try netfabb Basic here: http://www.netfabb.com/basic.php