That’s some nice looking geometry. Hmm, from your initial image, the curves looked to be straight segments. But when I look at the second image, they look curved.
Dynamo is limited by what’s possible to do in Revit. As you may know, Revit’s walls can take in only straight lines and arcs (circles in revit are made up of two arcs) and can not use any breps (nurbs or spline curves). So unfortunately, there is no way to merge the curves into a single entity that can be accepted by the wall creation node.
Since your curves are actually breps, we’ll need to approximate them. The built-in node “Curve.ApproximateWithArcAndLineSegments” can do the job, but is too aggressive with the tolerance and you can end up with hundreds of curves just from a single brep. That can be disastrous on a larger project. (and might not even work because some of the segments will end up being shorter than revit’s built-in limit) I suggest you try Lunchbox’s “Curve to Arcs by Division” node instead. It can accept a tolerance parameter (in the form of a division count) and that way we can gain a finer control over the number of curves that we send over to Revit.
Alternatively, you could look into simplifying the way in which you created your curves.