I'm a student in architecture and the attached file is an attempt to create part of my physical model - the part I would have a hard time building with sticks or wire or chipboard. Using Netfabb, I've worked manually to reverse the normals of the red faces. Now I'm left with the red faces on the helical truss, but the amount of work to reverse all these tiny faces is tremendous and I was wondering if you knew of a software that can do that for me. Netfabb identifies all these faces and colors them red, why can't it reverse them as well? The trick on that helical truss is that it's made of hollow tubes so there might be inverse normals within the truss itself but I can't see them. I'm happy to turn that truss into a filled tube (or rod) if that helps with the 3d printing (although I realize it would be more expensive). I appreciate your help and advice on this matter!