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...

That's great Barry, you cracked the code!

So it's making the second cut by intersection with a tube instead of a second planar cut.

- Michael

Sorry if i make an Iso Curve on these slopes (ring2 by Barry) i don't obtain same length ? ...(idem for the second one 1.29...)

There are two 3dm files of interest.
1. Lara's RingCutter.3dm
2. Barry's Ring2 solution. Import this on top of 3dm #1.


To see what is going on, Remove the 4 tops and 4 bottoms of Lara's(Mala's) cutting boxes. Also remove tops and bottoms of Barry's cutting boxes.
The 13mm tube is cut by the 26er cutting planes. (Curve is sort of ellipsoid?)
Barry has swept a 1.3unit radius circle centered on the inner tube cut. It is Rot (RED). (There are 4 red tori_ellip.)
The 15mm tube is trimmed ..... by these red tori_ellip. This cut is DIFFERENT that the cut of the 28er cutter.
The only need for the 28er cutter is to get the initial radius of the red torus_ellip.
(Edit/correction...Barry did do the cut of the 15mm tube with the 28er cutter, as an earlier step.)
Edit see Barry's next post, gif.

So the width of the bevel (winkle) is 1.3 units. Well, 1.3000001 units anyway.

- Brian

........Loft........ the larger and smaller ellipsoid, and a tiny bit more geometry to join the 13mm sections to the trimmed 15mm sections, and the "cones".

The 13mm tube and the 15mm tube remain as large tori, with circular "right angle" cross sections.

Very cool Barry.

Hi,
this is the method I used.(see gif below)
Pilou your correct the iso's are slightly different +/- 0.02 mm but this maybe a display issue.
Cheers
Barry

Edit: Added loft instruction.

Perhaps Barry's small circle sweep could be made to the larger toric_ellip, instead.

-Brian