Hello everybody
Now I’m looking for an optimal path on the terrain and I found an example of how it can be done (I’m attaching a link). This script works on the principle of finding the control point that lies closest to the end point. I would like to refine it by adding an analysis of the angle between the constructed lines on the path of these points. If the angle is greater than N value, then the next point will not be the one that lies closer to the end point, and the other one will be the second (and the one that is further from the end point). Please help to implement it.
Thank you.
it looks like this feature is already implemented in that definition?
at step_2 the Gradient-Divisor slider lets you chose how much % of the Step you want the next point to fall/rise in relation to the current one
then it creates a (cylindrical) Loft that will intersect your original terrain-surface only where the terrain falls within the Gradient-Divisor slider range → [-max_slope , +max_slope]
so, for instance, by setting your Gradient-Divisor slider to 0.15, you are setting the maximum slope percentage to +/- 15%, which I believe is what you are looking for? 
I would try decreasing the step value to about 1/4 ~ 1/5 of the one used in the yellow path
posting your gh file with internalized terrain geometry would also help
Please don’t double post:
Hmm, I thought I added the files.
Here they are.
Wayfinding.3dm (3.1 MB)
Wayfinding.gh (23.4 KB)