Problem with Closed surface

 

 

Hi people, Im new in here and this is my first topic. Im from Brazil, so my english is a litte amateur, sorry about that.

So I have this surface and is a closed NURBS but when I import into revit some Isoparms appear and make the surface not-continuous. You can see this in section view and in plans.

Does anyone have any suggestion to resolve this problem?Closed Surface