only apply surface manipulation inside sphere

Only apply surface manipulation inside sphere, that is what I am trying to do. The original formula comes from Shy Tavori of youtube titled 'Grasshopper Bump Texture' (see youtube link below text).

I want to have more control over the surfaces. Working with attractor points is an option, but I choose for a BrepInc component in order to select a specific area of surface points. I think it works the best.

The problem that occurs now is that I cannot figure out which wire I have to rewire in order to only manipulate a specific area. I was looking for other examples. Which component do you know that could help besides Cull Pattern?

Later I want to apply more manipulation on top of each other by summing different manipulations.

And don't take to much time for it if it is to difficult or take to much effort. I am new and I maybe have to learn more scripting instead of asking such 'difficult' questions.

https://www.youtube.com/watch?v=nb7EGf5T8Rc&index=11&list=P...