I tried to import a shell extruded by a free surface into Revit via DirectShape of Rhino.Inside. However, I found that this shell made the graphic performance extremely low in my Revit project. So is the DirectShape node in Grasshopper very unfriendly to curved surfaces?
Did the shape turn into a mesh with a lot of triangulated edges?
Did you make the rhino model or import it?
No, I just created a freeform surface in Rhino and extruded it. Then I used DirectShape node in grasshopper to transmit my extrude into Revit. I didn’t use any mesh tools. All operations were in Rhino surface workflow. And in my Revit project, there was only the extrude I imported.
I first met DirectShape in Dynamo. And at that time, it was simply a triangularization tool. All the curved objects generated by Dynamo would be turned into mesh-like objects in Revit projects. It was very unconvenient.
I’m a bit concerned about the performance of curved objects imported via Rhino.Inside in the future. After all, one of the most attractive features in Rhino.Inside is that it can bring a lot of nurbs objects easily into Revit projects.
Can you send the rhino model here? We will take a look.
There are limitations to revit’s modeling engine. So, we need to work with what they can do.
revit concept.rar (12.0 MB)
This is my test project. It seems that although the geometry kernel of Revit allow me to draw free form, the efficiency of modelling with surfaces is nightmare. These objects are just shells. Once we try to add panels, it will be horrible.
Those are complicated shapes. I am not clear how the performance is being measured? What do you find is slow in Revit in this case?
For me selection and view rotation are fast. There are a few ways to get geometry into Revit. Directshape is the simplest, but most of the time is not the best. For instance using Type definitions for a push instances into Revit. Here is a short video on using type instances instead: https://www.rhino3d.com/inside/revit/beta/samples/column-family-along-curve
I can work on this once I can measure performance in the same way.
There are many many situations that Rhino models are still going to be required for fabrication of complex forms and projects. Then using Revit to generate the 2d drawings. You can imagine on a large project the 3d detail model might still be in Rhino. For instance for a project like this, Rhino is still going to be the driver:
https://wiki.mcneel.com/webinars/morpheus
Parts like floor plates and visible shell might get to revit to see the elevations. But the process is not always going to be push everything into Revit.
Thank you for your advice! 
Revit or Rhino seems to always be a question. But the big model workflow from ZHA is inspiring for me!
Rhino works very well in medium and small projects with fully detailed models. However, Rhino seems to be a bit limited to large projects with detail interior and furnitures. I tried Rhino in two of my large projects with several buildings in them. And the efficiency was not very satisfying even I used blocks and mesh object. (orbiting at a speed of less than 7fps after convertion). RAM was full(i7 6820HK, 16GB RAM, GTX970M), and Rhino broke down frequently. That’s why I turned into Revit. However, the free modelling ability in Revit and interoperability between Rhino and Revit were horrible compared with pure Rhino workflow. Then I started to learn Rhino.Inside.
There’s still a question. In the Rhino-Revit workflow provided by Rhino.Inside, Revit is the main body, and Rhino provides its amazing free modelling ability. However, the horrible efficiency of freeform geometries in Revit limits freeform modelling, one of the most important features in Rhino. Therefore, what’s the role of Rhino.Inside? Only a bridge to access powerful Grasshopper plugins?
BTW, it seems that Autodesk still concentrates on developing various advanced functions rather than optimizing performance. Single-threading forever. Once Rhino achieve the stability of Revit and will not break down in large projects, it will be the best design tool for architects. But now I have to tolerate the bad performance of Revit. After all, it’s stable.
Right now it is best to use both. Understanding how to use them to compliment each other.
I always say that rhino.inside.revit will answer many of you questions. But, it will also bring up just as many new questions about workflow.