How to limit Voronoi generation to a planar/trimmed surface?

[Nandini]

I want to generate voronoi ONLY on the white surface. However, it ends up being like this:

The voronoi is also generating on the hollow/trimmed areas where it should not.

[HS_Kim]

Here’s a simple demo.

RegionDiff_Demo.gh (12.4 KB)

[Nandini]

Wow thanks a lot! I am a beginner and this really helped! Thank you!