How to convert Surface to NurbsSurface?

[shushenrui1996]

Hi. I'm trying to convert some kind of surface(such as cylinder/ revolved/ ellipse...) to NurbsSurface and then do brep data export. All I can find now is ExportUtils.GetNurbsSurfaceDataForFace() method. But it only support pevit api over version 2017 and I'm not sure whether it is suitable for all these kind of surfaces. Is there any other way to do this? Thanks!

[caroline.gitonga]

Hi @shushenrui1996,

There has been quite number of discussions on the same and I understand there is some limitation to achieving creation of NURBS Surface.

Have you tried to convert surface NURBS Surface form the end user Revit UI manually?
In general, if a feature is not available in the Revit product manually through the user interface, then the Revit API will not provide it either.

You can have a look at below forum discussions on the same:

https://forums.autodesk.com/t5/revit-api-forum/how-to-create-a-nurbs-surface-given-a-gird-of-xyz-poi...

https://forums.autodesk.com/t5/revit-api-forum/how-to-create-nurbssurface-using-revit-api/td-p/96058... 

https://forums.autodesk.com/t5/revit-api-forum/nurbspline-creation-error/td-p/4831565