I´m not sure. I didn´t find THE solution in your proposals. Mainly I mean the ideas/constructions with 3d-files I took a look at. The others I may not verify. My english is not so good, as you noticed meanwhile.
The main problem what you perhaps not noticed is that the cutting direction is not horihzontally or vertically in 90°.
I put the ring with the cutting directions as file here...
cu...Mala

P.S.: I extractecd now the profiles. If it it would be possible to aling the littler circles to their bigger neighbour circles it could work. But how?

These are not circles!

It's like i said from the beginning Ellipses! :)

The more easy : make an Offset ineternat from the External Ellipse et voilà ! :)

Then move along the circular perimeter internal and you will have your same measures of your troncated volume wanted!

(troncated is not show here but very easy to make with all these advices :)

It's your choice after to want a circle inside but you will not have same distance between big & little section!

Here you have an ellipsoïd !

Hi Mala,

> The main problem what you perhaps not notices is that the cutting
> direction is not horihzontally or vertically in 90°.

Ok, but if a cutting direction that is not 90 degrees does not make the kind of result that you need then why do you want to use it?

As best that I can tell (I'm still not sure) it seems that a cut made with parallel planes at an angle does not produce the kind of geometry that you want.

- Michael

Hi Mala, maybe after you do the outer cut, you should construct a tapered extrusion from the resulting edge and then use that to cut the inner tube with.

That looks like this:

Cut outer ring with angled box:




Do not cut inner ring with another box, instead generate tapered extrusions from the edges:



Make one on each side, use the "Flip" option in tapered extrusion for the other one:



Now it's these tapered extrusion surfaces that are used as cutting objects and also cut by the inner tube as well. When combined after the pieces are trimmed it will look like this (3DM attached also):



Is it right? Is it a uniform angle of the transition surface the thing you're trying to achieve?

- Michael

You have exactly that you want except the little middle part is not a cylinder but an ellipsoïd!
The other part is a cylinder!
There is yes the same distance between Big "section" & "Little" section (ellipse) around it's axe

Always of that because your sections are not PERPENDICULAR to the perimeter !!!
Offset sections (ellipse) Extrude Sweep and finally Loft the little extremities between them

Hi Mala, maybe another possible method would be to make a version of what you want along a straight line so it's a cylinder and then bend that into a circle using Transform > Deform > Flow.

That would produce a slightly different result than the tapered extrusion one above, because when you cut the toroidal shape with a planar cut, that produces some asymmetry with that cut being planar but the other side where the tapered extrusion intersects the inner tube will not be planar. With a Flow method you would have both planar cuts in the base shape and they would both deform when the shape bends into a circle using Flow.

You would use curve to curve flow for that with a line down the center of your cylinder as the base curve and a circle as the target curve.

- Michael

Flow is very cool but... :)

Or maybe what you need to do is to start with a kind of center line between the cuts, construct an extended angled surface from that and then use that surface to intersect the outer and inner tubes rather than using any plane to intersect them.

- Michael

Hi Pilou, re: "Flow Not Equality", if I maybe understand now (not sure!) the desired result has to do with a uniform angle, not equal distances. It's probably not possible to have both of those characteristics at the same time, it's either one or the other.

- Michael

Yep the geometry is the only judge of the possibility...
...but what is wished is not very clear! :)
(Extrusion & Loft gives same angle & distance)
Texture By Taron

Tried the taper command. But the angels are different. Not the way...

Frenchy: Please...the loft option in the extrusion - which one have you choosen?

Hi Mala, with the tapered method the angles will be the same with respect to the cut plane. If you need them consistent to some other measurement maybe you will need to construct the angled surface how you need it first and then intersect pieces with that.

- Michael

Visual!



The angles are the same. in the opposite sides and directions. Because the chamfer is on the opposite sides and direction.

If the cuts were "Mirrors", the angles would match, as the user is wanting.

Here is an example using a fillet...

There is nothing different about that fillet. It is a RADIUS all the way around both sides. The "same" radius.

Where the pinch points are and where the open spots are, depends on the angle of the surfaces to each other...

If you want them to "Match" at the same "OPPOSITE" side, the angles have to be the same, "OPPOSITE"...

Burman, thanks for your thoughts. I cannot proof it without the 3d file. But I guess a signifikant mistake in your construction is the angle of the cutting. Did you use the cutting cube in one of my previous files? I guess no. Yours has an perpendicular cut. But thats not the right angle...cheers, Mala

Hi Lara,
is the attached what you need.
Cheers
Barry

Updated Zip.
This gives constant slope length.

YES

Hi Lara,
I have updated the file as I had trimmed the inner and outer diameters and this was not correct.
You only need to trim the outer diameter thus giving a constant slope length.
Cheers
Barry

Hi Lara,
""""""Did you use the cutting cube in one of my previous files? I guess no. Yours has an perpendicular cut. But thats not the right angle...""""""

No. My post was not a solution. I was responding to the post where you asked "why" this was the case and you noted that the opposite sides matched.

I created an illustration to show "why" and how you can't do it with a fillet/chamfer or "winkle"....

Sounds like Barry is bringing an understanding and solution...