Voronoi on non-planar surface

Hi everyone

Im trying to apply a voronoi pattern onto a 3D volume (pretty close to half a sphere). 

I was wondering if there are any way to perform a voronoi onto a non-planar surface without involving the project or morph or brep/brep intersection components. 

I'd like to keep the information concerning the voronoi cells.

Thanks!

And theres a screenshot of my definition and model!