You're better off either cleaning up the undercuts by hand, or milling your sculpture in parts to be able to mill undercut areas and then assembling.
5 Axis machines and the software needed, are far, far more expensive, complicated and difficult to tram/align then 4 axis machines.
If it has to be milled, has to be milled in one piece, and can't have any unmilled undercuts, try to farm it out. Cheaper and more timely in the long run.
You can also look at Rapid Prototyping. |