Meshmixer is the ultimate tool for 3D mashups and remixes. Mash, mix, sculpt, stamp or paint your own 3D designs, or start from over 10,000 models in the Gallery. Now includes direct 3D print support.
 
some news:
  • New Preferences dialog to centralize settings
  • Improved 3D Print Services integration
  • New Hollow tool, with escape holes (auto-generated and interactive – try double-clicking)
  • New Bridge tool
  • New Thickness Visualization tool
  • Improved Support Structures for 3D printing, with new Presets and Support Graph Optimization
  • Make Pattern now has Linear and Spherical Gradients, better behavior for sizing parameters
  • New Select Visible command (under Selection / Modify)
  • Project Face Groups and Minimum Thickness options in Make Solid tool (min thickness requires Accurate mode)
  • VRML (.wrl) export (with vertex colors)
  • Improved Drop Solid behavior, Create New Part option
  • Smooth boundaries improvements
  • Better behavior of Remesh when smoothness=0
... and more!...

 For more info: http://www.123dapp.com/meshmixer-alt