Rhino/Maya Integration

Hello all,
I am having trouble utilizing Rhino/Fusion files (exported from rhino) and animating them in MAYA. The files will often come in fine, but the minute I animate them (rig them up) they completly fall apart. Obviously I have searched this problem, and there is alot of documentation about simply importing geometry, but making that geometry “animatable” is where the problem occurs. Any ideas would be great!

before exporting as mesh object, is better to convert them inside Rhino and then weld all vertices of each mesh, later export as mesh.
I do this when I wan to sculpt something modeled in Rhino and every object remains closed.