Delete the error surface and make a new surface
After rebuild the surface. All the surfaces can import. Then join them to one solid.( there is
Found 55 edges total; no naked edges, no non-manifold edges."
Then I have the same issue as the previous object
I’m importing this surface with no issues both in Metric (3dm and Revit model) and Imperial (3dm and Revit model). This probably has something to do with your Revit and 3dm model units. Which are you using?
‘Add Form’ tries to export the geometry as an extrusion if the Brep is an extrusion like.
There were a bug on that code. That’s why the “Object reference not set to an instance of an object.” message. We have released a new release with a fix for this today.
We have fixed this and Object.3dm now transfers without problem.
The other one is a bit more complex, with the current state of Rhino.Inside you need to clean it a bit.
One problem is this surface is almost planar but is not.