# 3-Intersection Sectioning

In this Grasshopper Lesson, I will show you how you can use intersections to design the sections of a parametric model. You can use this technique to control your sections. First, we will make a series of lines and then by using the intersection technique, we will produce the sections.

## Comments

## Jason

Hi, I am wondering how can I create the same intersections in/on a surface? I am trying to pinch a surface and create those sharp angles but I am not sure how to achieve that without the individual rails. If you have any advice on what I can do that would be greatly appreciated.

Thank you

## parametric

Hi Jason

Try contouring the surface and then use a “curve on surface” to make a parametric curve. Intersect the sections with this curve and move the point in the normal direction (you can use evaluate surface to get the normal direction!)