I'm trying to print 3D models of nonorientable surfaces: Klein bottle, Kuen surface, Boy surface, etc.
However, these tools can't restore orientability, which is required for 3d printing. (The printer must know where the inside is, to know where to deposit material!) At any line of self-intersection, the two sheets of the nonorientable surface disagree as to which side is "outside." In MeshLab, one sheet is black. In netfabb, red. Those triangles are called flipped; their normals are reversed.
What approaches are reasonable?
One simple way to transform any non manifold, non orientable surface into something that is printable is to "inflate" it so that it is no more an infinitesimally thin sheet. You can do that in MeshLab by using the uniform resampling filter and setting on the 'absolute distance' option (to get rid of non orientability) and specifying a reasonable offset (1% ~ 2%) and a reasonable precision (0.2% ~ 0.5%)
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