Projection of points into surface and culling point in curve

Hello, 

I am trying to project several points into a surface in z direction, however I am having trouble with that. In a step by step explenation, the definition should

1. Project the points on the surfaces perpendicularly

2. Detect by point in curve method wich ones are inside the curves of the previous surface

3. Delete the curves that have a point inside them

Thank you