generative modeling for Rhino
it looks like your geometry is either very very small, very very large or very very far away from the origin. Meshes are stored as single-precision data in Rhino whereas nurbs data such as wireframe curves is stored as double-precision. This means that meshes don't behave when they contain very small or very large numbers.
The only solution it to make sure you pick common-sense units (i.e. don't work in millimeters when designing a city, don't work in kilometers when designing a hand-held) and keep your geometry near the world origin point.
Further information: http://wiki.mcneel.com/rhino/farfromorigin