Clean Subd to Revit?

Hi guys, ever since I opened Rhino.Inside I’ve been trying to find ways to get complex subd’s to Revit (ideally as masses that can be Divided or even just forms that can be cut in sections properly as walls/floors or similar categories. Direct shape by geometry seems to give me the result (on the right in Revit) no matter if I reference in the subd or the nurbs converted version of the subd. The example on the left in Revit is just a DWG export from Rhino to Revit and inserted in an in-place mass family, same works for inserting in an in-place model family, this works very well manually. Any suggestions to achieve the same cleanness through Rhino.Inside? Thanks!

Can you send us one of the SubD objects in Rhino and we can work on the translation. Many times the problem is short edges. Revit does not like edges that are less then 1mm or so.

We can do some inspection of the geometry through these various products and try to determine what is different.

I cannot tell from the images if the SubD you have there actually has a ver short edge at the start points. It almost looks like the Subd was made of Triangular mesh faces?

You can send the model through our upload page: https://www.rhino3d.com/upload

I will upload the the model in a bit. The model is not small, I’m aware of Revit’s short lines problem, the model is atchitectural scale and wasnt made up of trianglated meshes in Rhino, some parts become meshes in Revit after the “bake”. Byw most SubD’s of this level of complexity are doing this for me, this doesn’t seem to be a rare case.

Hello uploaded my SubD file here, hope it helps.
SubDTest.3dm (1.3 MB)

Thank you for the file. We will take a closer look.

I also found just a single patch will show the problem, which I logged here: https://github.com/mcneel/rhino.inside-revit/issues/175

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Right! Thanks a lot. By the way, one way we’ve overcome this in Dynamo was creating a FamilyInstance.ByGeometry, which I think would export the geometry to either DWG or SAT and then import it into a family and load that newly defined family into the project. (Category and Material defined).
That could be a cool addition to RIR, cause then we can bring Rhino Geometry in as families without tedious tricks.

Arek -

It is a backup strategy to rely on the DWG or SAT mechanism. At this point we keep learning how Revit like its surfaces and BREPs. Within Rhino we hope to be able to modify the geometry in the translation ourselves, so you will not have to worry about it.

In this case it looks like Revit is converting the surface to a Hermite surface. Perhaps this is a direction we can take. We will see how that Github issue works itself out.

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Alright great, of course a translation would be fantastic. Thanks for everything. :slight_smile:

There is a workaround until McNeel finds a way to make SubD work with Revit. But plz work on solving this issue McNeel guys :). The old TSpline still works well with rhino 5.0, if you can get your hands on it, you might have to export in 2.0 format for Revit. If the shape gets to complex it will properly not work well. Also, Autodesk Fusion seems to have made adopted the old TSpline codes into their program, works really well. Import with .obj (good square mesh), convert to TSpline, convert to Brep, export as .sat and vola you have have smooth and nice shapes into Revit. Hope is helps.

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