MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
If you slice with exactly 0.2mm layers as indicated, there should be a skipped layer between the external sphere and the base. Essentially, bottom layers act as a raft for the outer sphere, which you can then break free using a screw driver as shown in the photos. Also, if you read through the other comments, you'll find additional tips on getting the parts freed up.