I wanna know how to convert Rhino Planar Surfaces which are made with Nurbs Curves to Revit Floors or Slabs? When I use linear curves for converting, I get no errors. But I can not convert surfaces which are made with closed Nurbs or Interpolated curves ? Do you have solution for this?

If you split your closed curves into 2 or more curves, it should work - there is a Revit API limitation for which closed curves are not supported, and weâ€™re actively looking into workarounds

You could also be bumping into Revitâ€™s own NurbsCurve limitations.

Not only does it not support closed curves but it also wonâ€™t support a wide range of non-closed nurbs curves if the knot vector is not within some very simple rules revit enforces.

The curve-splitting strategy Matteo is suggesting will work to some extent, but not every single curve will.

What are the errors youâ€™re getting on Revit when receiving said floors?

First thank you for your answer. I did as you said and I got result. But this is not what I wanted. I wanna get smooth curve, but I got â€śsmoothâ€ť curve with divided into â€śnâ€ť number linear segments

Thank you for your answer, I tried Matteoâ€™s method. It worked but I got linear segments instead of smooth curve. Few months ago I tried Conveyor by Provinggeound. Actually it was working on nurbs curves while I was converting them to Revit Slab/Floors. Thatâ€™s why I wanna find solution about that. When I convert Rhino surfaces to Revit, I get error â€śUnknown geometryâ€ť. Even in Rhino.Inside.Revit, Nurbs curves are not supported

Could you share more details about the error you were originally getting on Revit? Additional screenshots/gifs do help understand the problem with less back and forth.

For any curve that is not supported by revit, we will fallback to its PolyLine representation. If this is happening after splitting the curves, Iâ€™m afraid itâ€™s highly likely that the curves youâ€™re sending are not compatible with Revit (even after splitting). But then again, Iâ€™d have to see the error youâ€™re getting to be sure.

Can you share the file/stream youâ€™re using?

Is the â€śUnknown Geometryâ€ť error youâ€™re getting a Speckle error, or where you talking about Rhino Inside there? Not sure where that error would appear on our side

If Rhino.Inside does not support this on their own Rhino.Inside Revit workflowâ€¦ Youâ€™re mostly out of luck My suggestion would be to simplify your geometry (lower degree, lower number of control points, do not interpolate â€śthrough pointsâ€ť, aka curves were the control poitns and the curve coincide).

But this will, in general, modify the geometry of the curve too.