returning to the curve after distance from point established

Hi, I'm writing some code to determine the coordinates of the points of a line that are r distant from each other. I'm using an intuitive process of convergence toward a desired r through a distance d in a loop.

 while abs((d-r)/(d+r))*100>t

                if d<r
      x(inizio)=(x(fine)+x(inizio))/2;
      y(inizio)=(y(fine)+y(inizio))/2;
      d=d+sqrt((x(inizio)-x(fine))^2+(y(inizio)-y(fine))^2);

                 else if d>r

       x(fine)=(x(fine)+x(inizio))/2;
       y(fine)=(y(fine)+y(inizio))/2;
       d=d-sqrt((x(inizio)-x(fine))^2+(y(inizio)-y(fine))^2);

The problem is that since I create iteratively new points ( x(fine) and so on) every time I'm going to find new coordinates that are not on the line I inputed in the script. Do you have any idea how to stay on this line? Thanks a lot, I know I'm not clear (maybe if you ask me something directly I'll make my self clearer).

[Oleg Komarov]

Do you have the analytical expression for the line?

Answer 1

[Sean de Wolski]

• FEX:interparc
• FEX:distance2curve

Some files that may be useful to you.

Answer 2

[Giorgio Scolozzi]

Thanks for your time Sean, but since I don't have an analytical function..... or I can still use interpolation with just coordinates? my data set are just point traced with a plugin (NeuronJ)