Vb closest point on a curve

Hello,

I just started coding with vb and i have some trouble.

I am trying to do a kind of drainage simulation.

The code is structured as so:

I take the relative top crv of a topography and divide by a nb of point.

Then these points look for the closest point on the topo crv under it. It repeats this operation until there are no crv under it.

Unfortunately it seems that i've a problem with the end condition of this code and some of the point stop searching.

Thank you for your help, here's the file in attached