Hi Pilou,

> If i good remember when 2 points or more are overlaped in the same x,y,z
> there was a red square... but don't remember in what Function(s) and if it's always living! :)

The red square is if you have 2 of a single curve's own control points (the points you see if you select one curve and use Edit > Show pts) stacked up on top of each other. That has to do with the points just in one curve, not anything about multiple curves touching each other.

- Michael