Michael - I got it. Thank you!!!
Mala

Hi, I noticed that there is a little construction problem - different differences at the lofting parts. See it atached.
I cutted the tubes with two different sized cubes. The littler one is 26 mm for the smaller ring. The bigger ring is trimmed with cube, 28 mm. Then I had to rotate the cubes horizontally for a special winkle I need. Then I cutted the two rings with the cubes. The result, in the file, are different distances at lofting-surfaces.

How would you place at beginning the cutting objects in order to avoid the distance differents at the lofts? Ideas?

kind regards, Mala

Hi Mala, sorry I'm not understanding the problem. It's just a normal fact of geometry and
mathematics that the projection of a rotated object does not keep equal distances in the projected view.

For example if you have a square in the Top view:



If you rotate it so that the plane of the square is not aligned with the top view:



Then the projection of it in the top view will not be a square with equal length sides anymore:



Your lofts have equal distances in 3D but they are at an angle to the top view so it is normal that the
projected lengths in the top view will not be equal.

- Michael

hmmm´...ok, Michael.
I tried an other way...but the result was exactly the same. I made a offset of the two big circles and moved it for 1 degree together. Sweep along the segment.
Perhaps someone has an idea somehow...best, Mala

As a cube can't have the same direction of 2 edges from the center of the circle
only when its 90° or 180° so you can't have that you want where you are!

Sections will always inclined so difference of distances between the 2 circles!
(in fact Ellipses & Circles)

Here little cube can't have 45° of the Angle center!


Here circles are drawn on the face section for show the deformation!
(they will be also ellipses by these triming lines!

The intersection of a cylinder and a plane is an ellipse.
The intersection of torus and plane is a toric section.
I think that your smaller ring is NOT a torus.???
So make the smaller ring by revolving a circle?

I need more study:-)

Brian

Or, per Michael, slant lengths are different, in different places, by the geometry.

Conversely, if equal slant lengths are the goal, the inner ring would have to be modified,
To be squished down to an undulating "ellipsoid" (or toric section?), cross section?

You have only circle sections of a tore when the triming curve/plane is perpendicular to the big perimeter! :)

Hi Lara,

re:
> I tried an other way...but the result was exactly the same. I made a offset of the two big circles
> and moved it for 1 degree together. Sweep along the segment.

I'm sorry but I still don't understand what the problem is.

So you've got this:


Looking at these edges by themselves:


In the Top view, the distance here on-screen:



Will be different than the distance here on-screen:



So yes that is true but it's just how projection of a rotated shape works.

If you have a regular truncated cone like this:



If you rotate it:




Then view the rotated cone in a top view projection it will look like this:






That's normal and it's just how geometry works with projection.

If you wanted the projection to look like this:



That would need a slanted cone rather than a regular cone:



- Michael

Hi, Michael.
I assume that it is necessary so.

Hi WN, yes it would be a kind of simpler case if the cuts were straight up and down like in your example. In Mala's case they are slanted.

- Michael

Michael, what's wrong with this option? The difference is there but less.

Hi WN,

re:
> Michael, what's wrong with this option? The difference is there but less.

Well it's different in shape from the original design which had these profiles on parallel planes:





In your version those spots are not on parallel planes and so not equidistant as measured in 3D. But that's the kind of thing you would need to do to make the top-view projection of it to look equal, similar to the slanting cones that I showed above.

It's not clear to me what the desired result is - should it be equal spacing in 3D space, or should it be equal spacing of projected shapes?

I think Mala will need to give some more information on that.

- Michael

Thank you Michael.
Yes, we are waiting for what Mala will say.

Thanks a lot for discussion. Best is I try to make it clear what the goal is.
Hope the drawing makes it clear.

Hi Mala, I'm very sorry but I don't understand the drawing at all.

- Michael

Hi Lara.
Can you tell me which method is closer to the goal, or none of them is suitable?
If you want maximum help, you will have to try to explain.

Hi Lara,

OK, Silikone is a rubber-like substance?

A winkle is a type of sea snale, so I will translate it as a bevel, or a beveled ring, or a chamfer,
or chamfered edge surface.

You require that the chamfers be the same width?
And/or the same angle with respect to the outer torus?

The cross sections of the smaller torus-like "ring" will probably be different than each other,
perhaps non-circular, perhaps non elliptical, to match the chamfers.

The slant cuts are at different angle directions with respect to radial lines from the center of the big torus, which caused the different bevel widths.

Make the bevel cones the desired uniform width. Then make the smaller pseudo-torus.

-Brian

Bobbel has numerous translations from Dutch.

Extend the cone-like chamfers, to make them wider, then cut them at the desired uniform width.

Then make the smaller ring to match the new chamfer edge.

-Brian

I imagine that the "cones" are oblique, and not true geometric cones?

I made a drawing. Hope this will make it clearer.