3d Voronoi across intersecting Surfaces

I am trying to use apply 3d voronoi to polysurfaces (made from different lofts).

i need the result to be mostly regular polygons so i have used the mesh of origional surfaces as an input for the voronoi. The alrogithm works perfectly on a single surface but the 'surface' input doesnt seem to accept joined polysurfaces.

I have managed to circumvent this by using a patch through the mesh to generate a new surface, but for some reason it adds extra lines cutting along the entire surface which ruin the effect.

this is result of using a single surface, no patch that i am looking for:

I will be eternally grateful if anyone can help, as i am quite new to grasshopper and rhino...

(ps. please be aware after you set mesh component it will take 2 mins to run)

thank you