Thx. French Pilou !

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

Thank you Michael.
Regarding moving curve points in the 3D view :
It quite often happens that a point moves jumps far away
in any direction from its original position (no snapping activated),
very different like I am used in Cinema 4D, where I can move and
place points exactly in the 3D. What can I do to avoid these
big jumps ?

Hi Tom, if no snapping is activated, then the mouse will track along the construction plane, shooting a ray out through the mouse point and intersecting it with the construction plane grid.

If you're looking at the grid at such an angle that a small distance of the mouse moves a very far distance along that grid it will have the kind of effect that you describe.

To avoid that, angle your view so you're looking somewhat more downward at the grid instead of having it positioned where it's going way off into the horizon.

Either that or you may need to set the construction plane to better accomodate the kind of thing you want to draw. Basically your mouse will track along that plane.

- Michael