Combing 4 surfaces to a single surface

Hey guys I have 4 single nurbs surfaces that when combined created a polysurface. I need it to be a single surface. Is there anyway someone could help me out with this?
4 surfaces to single surface.3dm(936.9 KB)

Hi Heaton - no… these cannot be combined to a single surface- one thing about NURBS surfaces is that they cannot have arbitrary topology, like a mesh can, they must be four sided in structure. This makes the two funnel shapes impossible to combine, for example. Why do you need a single surface?


Why do you need that to be a single surface? You have trimmed edges there, they can’t remotely be merged, you would have to reconstruct this from scratch, and even then the level of point-manipulation needed would be a bit extreme.

I need to be a single surface so I can use it in a GH script to create a diagrid structure. I tried having the top blend into each other and not be such a right angle but everysurface created was a polysurface so I could not use it

Does it need to be untrimmed? Because that would be impossible. The only way to try to make this a single surface is to reconstruct it, I dunno maybe starting out with a plane–I suppose Patch might give you a similar sort of start?–then move points waaaaay down for the outside and insides, and trim off.

You can accomplish something like that with T-Splines, but you wouldn’t get sharp corners.

With T-Splines using creases you can do it

The result will may a single tSpline but will not be a single surface when converted to a Rhino object.


T-Splines has a grasshopper component and he could achieve what he wants.

But I’m not sure about that.