Hi Tom,

> i did a search and it looks like that it is not possible to set up
> a curve (point on point) on an existing surface (loft / network etc)
> or to move the points of a curve on a surface ?!

The most usual way to put a curve onto an existing surface is to have a 2D curve and use Construct > Curve > Project command to construct a new curve that is projected onto the surface.

Also like Pilou mentions if you want to extract out a line in one of the U or V directions of a surface Construct > Curve > Iso can be used to generate those kinds of curves. Those ones will tend to be aligned with how the surface was constructed.



> It looks like it works only in the 3D view is that right ?
> And you need lots of points as only the points are projected
> onto the surface and not the curve as a whole ?

Yes, by default the "on surface" snap only activates when placing points in the 3D view. That's because basically the 2D views are more oriented around keeping drawn things aligned to that particular view plane. When you're doing stuff in the 3D view it's more oriented around freely snapping things to 3D point locations.

There is a setting you can alter in moi.ini to change that though, see here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6171.10

- Michael