X Axis Line on Surface

Hello!

A newbie question!

I'm creating a surface with point attractors. Then I want to change it into points, that will generate lines, then planes and I will extrude it into concrete slabs, like the Aqua Tower in Chicago.

The problem is: I cant change the Y axis of the lines to a X axis (blue lines on the picture). Can someone please help me? Sorry for the simple question but I'm for hours trying to figure it out.

Thank you!