First of all, none of your Rhino geometry seems to be referenced in Grasshopper!
By “(h)exagonal panels”, you mean the glass pattern of the windows right?
Instead of using a diamond grid, simply use a hexagonal grid? The hex cells can then be further processed, if you want to replicate the quad subdivisions from your reference.
Since your GH file isn’t working without referenced geometry, I couldn’t take a peek to indentify what causes this problem. My guess would be that your trimmed Vornoi cells are not clean closed polylines anymore. There might be something wrong with the trimming process?
One another thing to think about is that your reference shows a futuristic building that might or might not be based on a Vornoi diagram!? It’s really hard to say!
Judging from the rendering, I’d say that it’s probably based on a couple - maybe three to four - carefully selected, adjacent 3D Vornoi cells, and not a messy cutout from a 3D Vornoi diagram?
If anything, it probably was an elaborate modelling job, of that I’m pretty sure!
Furthermore, since your goal is to use pipes for the support structure, I just want to point out that pipes, even with variable radii, will probably never produce a comparable geometry.
I’m guessing here that you don’t want to replicate the exact same thing, so are you after a node-based logic for your pipes or should everything be one homogenous mass like in the reference?