Hi Pilou,

> Is that more clear? :)

A little bit... :)


> Of course the line / line with no Scaling is cool but
> i will whish to slide on the curve for some reasons :)

It is possible to get the slide along curve, but you have to position the source frame to the correct position so that it will map to the natural target location on the curve.

The main thing to focus on is that whatever direction the z axis is pointing towards in the source orientation, will get mapped to the curve tangent direction in the target placement, since when snapping on to a curve the axis is placed with the z axis along the curve's tangent.

So for example with your last image, if your source orientation is positioned with its z axis like this (z in red here):



When the target position is placed on to the curve, that same direction will be mapped to the curve tangent, here the curve tangent shown in red:




So the red line in the first image maps to the red line in the second image....

In other words, the z axis of the source position is what will end up matched to the z axis of the target position. Similarly the x axis of the source position matches to the xaxis of the target position and same with y.


The reason why it is mapped in this way for default positions is that it makes it easy to position a planar curve perpendicular to a different path curve.

But if the default mapping does not do what you want, you need to adjust the orientation by flipping some of the axis directions around instead of only using the default orientation.

My advice is to not worry so much about getting the "slide along curve" motion just by itself - instead try to focus more on what final position you want to get as the end result. If you are focused on the final position more it means you can do some axis rotations on the target position to get the final position how you need it.

I'm still not sure if you are able to get what you need now or not - doesn't the orient line to line tool give you an easier way to get the final position you wanted for your particular case?

- Michael