# Closed spline revit

**URL:** <https://forum.dynamobim.com/t/closed-spline-revit/82707>\
**Category:** Geometry\
**Tags:** revit, geometry\
**Created:** [November 3, 2022, 12:15am UTC](https://forum.dynamobim.com/t/closed-spline-revit/82707 "2022-11-03T00:15:24Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sabra.tarek](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@sabra.tarek](https://forum.dynamobim.com/u/sabra.tarek)\
**Post date:** [November 3, 2022, 12:15am UTC](https://forum.dynamobim.com/t/closed-spline-revit/82707/1 "2022-11-03T00:15:24Z")

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hello ,  
i am trying to do a closed spline in revit to model this geometrical shape in the picture but i failed.  
i drew a closed spline on autocad and impored it to revit , but when i create the geometry the results is not a clean geometry ( as in the picture ,those 2 extra edges )  
does anyone know how to model this shape in a clean way through closed spline or through any other method ?

 ![221](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/7/e/7e3b7cba3ebf4969e3bf0163829feb2827d6d981.jpeg)

Thank you for any help

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**Author:** ![gilberto.arechigaiba](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/gilberto.arechigaiba/32/204980_2.png) [@gilberto.arechigaiba](https://forum.dynamobim.com/u/gilberto.arechigaiba)\
**Post date:** [November 3, 2022, 10:53am UTC](https://forum.dynamobim.com/t/closed-spline-revit/82707/2 "2022-11-03T10:53:25Z")

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Hola Amigo @sabra.tarek buenas. Normally Nurbs Curves and Splilines are not so compatible with other geometry nodes and vice versa many nodes ask for a specific type of element Curve, Polycurve, Line and Nurbs curves etc, and I think that’s where your problem comes from, i sometimes use the node Polycurve.ByJoindedCurves to transform NurbsCurve into Polycurves this help me a lot, for your topic, If I were you I would first make a solid as regular as possible and then cut the solid with a specific profile, it is only a suggestion not a solution, you are the artist, I hope this helps you!

 ![Cilinder vs Surface](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/b/3/b36e20a0599b1c27260d5fe68da9e61b8490dde6.jpeg)  
[Cylinder vs Surface.dyn](https://forum.dynamobim.com/uploads/short-url/lDYYug2l7oNpb8srZX5dL2Mn9dJ.dyn) (34.2 KB)

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**Author:** ![Mark.Ackerley](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/mark.ackerley/32/79310_2.png) [@Mark.Ackerley](https://forum.dynamobim.com/u/Mark.Ackerley)\
**Post date:** [November 3, 2022, 1:18pm UTC](https://forum.dynamobim.com/t/closed-spline-revit/82707/3 "2022-11-03T13:18:42Z")

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Hi,

Just to test a native Revit process, if you draw a wall from a circle, you’ll see that it makes it as 2 walls, each a semi-circle.

There are things we can do in Dynamo (as Gilberto says) to make a seamless NURBS, or in AutoCAD, as you did… However I think that when they come into Revit it will generate Seams.

I did a quick play bringing in a seamless NURBS solid from Dynamo as an Import Instance, however even then, Revit created a Seam.

I hope that is useful,

Mark