Silhouette of lines and polylines

I am trying to get the outline of a group of objects( lines , polylines both open and close) these lines are the result of Make 2d in grasshopper, and I am trying to get the result as shown in the image (red line)
any help here?
thanks in advance

Hello, provided that the given set of lines are very clean, Surface Split would do. (13.1 KB)



thanks, I will try it give you a feedback