3D printing from Blender is going to get SOOOOO much easier with the new '3D Printing Toolbox' in 2.67. It'll include all kinds of calculations and visualisations including my favorite: wall thickness.
Ton Roosendaal writes:
It was about time to put a bit of focus on 3D printing tools in Blender once!
Dolf Veenvliet now is working for Blender Foundation on a new training DVD, to introduce 3D modeling to 3D printing enthusiasts, and to present the workflow for making proper geometry for printing. He works with Campbell Barton on a new toolset for 3D printing, which includes options for interactively checking manifoldness, wall thickness, weight, etc.
Dolf owns a Makerbot, and Campbell has a Lulzbot, so things will be tested well for home printing too. More advanced models will be submitted to Shapeways; like a full color Sintel statuette and the Tears of Steel "Quad bot".
The 3D toolbox script is currently being tested and reviewed by Sebastian Koenig for a local 3d printing company as well.
It can be found in any recent Build of Blender as add-on, named "3D Print Toolbox".
More news about the DVD and documentation for the toolbox will all be available around the next release, 2nd half of April.