This Helix/Spiral is cutting a thread. One end of the Helix/Spiral is on the Right Plane there for a triangle was sketched and coincident with Helix/Spiral end on the right plane. Part file is attached.

I have two questions:

     -How to confirm that Helix/Spiral end is on the origin plane.

      -If Helix/Spiral end is not on any of the origin plane how solve the problem?