Hi Pilou, so maybe some of your confusion with the 3D orient tool is that you're focusing on edges of your base object, but by default the primary thing that is actually aligned to is surface normals if the object being snapped on to is made up of surfaces.

So for example placing the orientation picker x/y/z location to this spot here:



The default thing that will be aligned with is actually this surface here:



The yellow line here shows the surface normal direction of that yellow face:




So that's the direction that by default will get mapped to the target position's z axis, and if you place the target position on to a standalone curve, the target position z axis will align with the curve tangent.

If you wanted to align some other direction than that, you would need to adjust the base axis frame, you can do various things like rotate the an axis by 90 degrees around another axis until it has the orientation you want to use.

But instead you may find the other Orient Line To Line command as mentioned above to be easier for cases where you want to position 2 things that start out all in the same plane.

- Michael

Thx for the detailed informations

Sorry if i was not clear in my explanations
The object was not in the good orientation in my previous file :(
I was fumbling and deseperate to not find the good solution!
(so the false image and file! :)
(but thinking that is possible to start from any position to anotehr one
--> perpendicular abode the curve)
Object on the top curve surface is the result wanted

So what must be the deductive reasoning for ovoid to test all orientation of the tripod axis :)
Of course I will exam all your infos above!

Here the new file! :)
http://piloumaison.weebly.com/uploads/3/6/2/0/3620514/slide_on_curve1.3dm

Is that more clear? :)

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

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

< So for example with your last image, if your source orientation is positioned with its z axis like this (z in red here):
This is my result of manually use the Function Orient! If you see on the image the little lift corner you will see the default orientation ;)


The line/line is perfect for one position on the curve !
(little trick) just take the first point on middle on the baseline objet, the second anywhere to the end line base object, and you will have easily the postion on the curve with a perpandicular helpers line ;)

And then call the normal orient for slide the object on the curve! Bingo!

But, now , i have learning by heart the tripod position for arrive on a curve // on the ground for win a using step function! :)

So now I am a little more strong for make video about the subject!
Thx for the help and sorry for my unprecise first image!

Just a question : does the last tripod of function "orient" position is memorised when you closed Moi?

And regulate the size of the tripod of the function Orient?
In the moi Ini?

and this one!
I have all disable Snaps except "On", (because I want slide on the curve) in any menus, in any options

But there is always trouble when I pass over the "ghost forms" of the original object position when I slide the object on the curve!!!
How avoid that?
If I make Alt, I am not more on the curve! :)

Hi Pilou,

> Just a question : does the last tripod of function "orient"
> position is memorised when you closed Moi?

No - in general points that you pick within some command are not remembered between sessions, and orient is no different than any other command in this regard.


> And regulate the size of the tripod of the function Orient?
> In the moi Ini?

No, there is not currently any setting for that in the moi.ini file - those line are scaled so that they will be a size of 150 pixels on the screen though, so they will maintain a constant size whether you're zoomed in or zoomed out.


- Michael

Hi Pilou,

> But there is always trouble when I pass over the
> "ghost forms" of the original object position when
> I slide the object on the curve!!!
> How avoid that?

You could move the original object off to the side somewhere so it wasn't directly on top of the area that you wanted to orient it on.

Or another possibility is to assign a name to your object and then while you are within the orient command you can go to the Scene browser Objects section and hide it and the wireframe outline of it will then be hidden.

- Michael

Thx for all these precisions