Polysurface problem

I’m experiencing problems with polysurfaces I got from a Bentley steelworks user through *.dwg and *.dxf

Many of the polysurfaces have their faces flipped towards inside and I can see into them.

I can explode and flip and it Looks alright, however when I merge the surfaces to a polysurface again I can see into the polysurface.

I have tried a few things like shrink trimmed surface to edge, rebuild, change degree…

Most succesful so far is when I explode the polysurface and extrude using the extrude surface command.

When dragging with the mouse I get this approximated shading which looks bad and I was wondering if anyone has a clue what the issue is?

Have you checked to see how far they are from the origin?


yes, the units are millimeters and the file is georeferenced in new swiss coordinates.

However this might be the problem. Actually it first occured when I moved non georeferenced geometry to the proper coordinates. I moved everything really close to the origin and the issue isn’t visible anymore.

Is there a problem with the maximum coordinate space?

Have a look at: http://wiki.mcneel.com/rhino/farfromorigin