Of course I have no problem when my Rail scaling is // and have some points down and on the Z axe
And also because I have made that with a curve line who have also only 2 points over the path on the Z! -works fine
And want to know if it's the same with a straight line

I have just asked for know if it was pertinent or not

In fact I suppose that this rail scaling can be considered as a sort of third rail?

Hi Pilou,

> In fact I suppose that this rail scaling can be
> considered as a sort of third rail?

Yes, kind of... It works though as a modifier to the sweep, the sweep will initially be formed with the regular rails you give (either one or two rails), and then if you set a scaling rail, it will modify all the generated profiles of the sweep to stretch out in the way that I showed in that previous illustration.

The "main rails" of the sweep control the placement of each cross-section more directly - the "scaling rail" just controls a stretching factor.

- Michael

My line of the first post was a perversion of the method pushed to the limit :)

Ps Not possibility to have the Rail Scaling only limited of the "upper" half side of the volume?
(don't want the bottom section follow the Rail Scaling)
The funny thing is that you can move after the points for adjust your form!

Hi Pilou,

> Ps Not possibility to have the Rail Scaling only limited of
> the "upper" half side of the volume?
> (don't want the bottom section follow the Rail Scaling)

Not with a scaling rail - it works by applying a scale transformation on the profiles, which does not easily allow for that kind of a "partial" scale in a general way.

But if I understand you correctly, you can get that kind of a shape by using a 2-rail sweep instead of using a scaling rail.

That would be a profile and rails like this:



Then when you do the sweep, select both of those as sweep rails at the rail selection prompt, instead of picking one as a scaling rail later. With both of those as sweep rails, the profiles will slide along the 2 rails which gives this kind of a result:



- Michael

yes but as my first volume is a 2 rails sweep (so Horizontal asymmetric side) maybe I can make that if the Rail Scale don't make half section
(not so a big deal :)

Hi Pilou, also when you start wanting to get a lot of control in many different areas like this, you may want to switch to the Network command instead. There you can add in a larger number of profiles.

But also it looks like assembling your object in halves works for your case too?

- Michael

yes assembling works fine!
I was afraid that horizontal section shoud be different after the rail scaling but all works fine :)