These two "orb" sculptures were the result of teaching myself the latest version (2.0) of MeshMixer: I wanted to see how easy it would be to draw a symmetrical stencil on a sphere and extrude it, turning it into it's own volume. Turns out to be pretty easy. I made orb01 first, and refined the process with orb02 that has a bit more detail.

MeshMixer will auto-generate it's own support structure, so there is a version of each orb uploaded with the provided support (see attached pic): You shouldn't need to generate any of your own. That being said, I couldn't get orb02 to print successfully with the provided support: At a certain point some of the supports would snap off, causing overhang print failures. Because of that, I provided a non-support version of orb02: Makerware did a fine job of auto-creating supports for it.
Both orbs were printed with these settings on my Replicator 1:

• Orange PLA, later spray painted metallic silver and gold.
• No raft: orb01 used the built-in support. orb02 used Makerware support.
• Extruded @ 220 deg, HBP off. Removable glass bed with blue painters tape.
• 2 shells, 10% infill. 270 micron layer height (lo res).