A screenshot is almost always useless. Better paste your Rhino file if you want concrete advice.
One thing is certain. Even if you properly surface model the primary domain in Rhino and then repeat (copy) it many times, the number of surfaces will be what it is.
I cant upload my file because it is too big. My problem is not copying.
The model was first created in SubD, then exported to Fusion 360 for further modifications.
After that, I continued working on the model in Rhino as NURBS.
During the SubD > solid >NURBS conversions, the geometry was naturally split into many trimmed surfaces.
Duplicating the model does not increase the surface count; the surface count comes from the conversion workflow itself.
Given this workflow, what is the best way to reduce or clean up the surface count in Rhino?
I think you have misunderstood @Lagom’s comment. Your model appears to contain an array of openings. He is saying that if you modelled one opening from scratch with low density nurbs surfaces and then copied (arrayed) that opening to complete the full set of openings you would still employ a similar number of surfaces - no reduction.
However, your model would be much smaller because the surfaces would all be less dense.
Of course, without seeing the model we can’t tell if you do have identical openings - if you don’t then arraying a master copy isn’t going to work!
Yes, the openings are not the same size — they gradually disappear towards the top.
To achieve this organic look, I modeled the entire form in SubD.
Later, I moved the model to Fusion 360 to merge the thin wire-like elements, because I couldn’t get clean boolean results in Rhino at that stage.
You mean that they become smaller or otherwise taper towards the top, which means that literally all surfaces are different.
In Rhino, you can MergeSrf two untrimmed surfaces, but that won’t be of use in your case.
It would have been better to NURBS surface model the primary domain in Rhino, with simple single span surfaces wherever possible, then stack multiple copies on top of each other, and then use CageEdit to achieve the overall taper.
I wanted the structure to pass exactly through the center of the X-shaped wires running inside it. For precision reasons, I therefore needed to convert the SubD geometry to NURBS. Additionally, this conversion was necessary in order to be able to properly join two different objects.
