Springs.FamilyInstance.ByGeometry not including all surfaces of solid

Hello everyone! I’m using the Springs.FamilyInstance.ByGeometry node to create a number of families from a Dynamo solid, but when the family is created and added to the project, it seems to be missing its top and bottom surfaces. The dynamo solid that’s passing to the Springs node seems to be completely solid, so I’m not sure why it’s not capping it. The view is in hidden line, not wireframe. Using Revit 2017.2 and Dynamo

.dyn attached, you need to select a couple of input curves to create the solid. Thanks!
help_180703.dyn (81.6 KB)

Looks very similar to the below situation:

Try exporting the geometry to a sat file with the “Geometry.ExportToSAT” node and then manually importing it in revit. If it fails, then revit just can’t handle it. If that’s the case, you could try to perform additional surface simplification by using the “Surface.ApproximateWithTolerance” node on all curved surfaces of the solid.