""""""""""> And this image is on FreeCad and show the curvature normal on B-spline and is possible to
> get the visualization of this on Moi3d maybe with a script?""""""""""

This "CCC" by Karsten Will give the graph.

http://moi3d.com/forum/lmessages.php?webtag=MOI&msg=6634.14

Then Max wrote a script that will give the "weighted point Data" for the curve being used

http://moi3d.com/forum/lmessages.php?webtag=MOI&msg=6257.18

A little further down in that last thread by max he made another command, with more options, which puts the points "On" the curve...