How to flat all the ending points of a group of curves on one line?


even if it isn’t clear, all the ending points have differents high

Maybe SetPt?
https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/setpt.htm

I’m trying but he allows me to align to World or align with Cplane, not with a point that i can decide

I would guess Extend>To Boundary. You can crossing select all the lines to extend (IIRC).