Personal workflow when you find it is always the best for you! :)

Ok, Michael...

Good!

Hope so!
I've to learn tons of commands and their uses.

Bye

Subdiv is maybe not for your case ;)
But can be useful for imagine creative forms!
there are for the moment only 5 principal functions ;)
Native Extrude + special SBridge, SsPlit,Sscale, Subdive
as you see fillet is special ;) And you can't made fillet on the "edges" of a volume subdivided!

Yes, exactly what I mean!
Usually, in Rhino, I draw a circle with the given diameter and then create a form; moving some points I try to achieve the model I need and use the circle as reference. So I try to be nearest to the circle, it doesn't matter of the precision, because when the ring is casted and polished it change its dimensions.
The important things are the setting for the stone that must be precise... but I can use nurbs with standard commands.
So, yes... it's good as you wrote!
I think that, starting from a cube, I can add faces following the guide circle to form a ring... right?

Thanks
Marco

Hi Pilou, first af all big thanks for your fantastic input, much appreciated !
One question: what do you mean by "special SBridge", is this different from
this version:http://moi.maxsm.net/files/scripts/sBridge.v.0.71.2015.03.26.zip
???
Thanks again + best wishes !

sBridge (plugin) is "special" function for Subdivision against "native" Extrude who can be used in certains faces for subdivision! ;)

Yes it's the Max Smirnov one! ;)

Many Thanks !

Hi Marco,
not sure if this is the result your looking for but this was produced by using half of the helix (outer diameter of ring).
I extruding it to max depth then trimmed as Michael as shown.
I then shelled it and filleted.
It was necessary to trim the solid where it was going to join in the middle as this was not flat due to the shelling.
I then copied the half revolved it 180 and joined.
Hope this helps.
Barry

Barry!!!
That is exactly what I expected to achieve!!!!!!

Thanks a lot

Barry,

I follow Michael advises and yours, but... how did you solve the issue in the point where it has to be join?
Mhhh...
In all this job, a profile is missing I think!

Thanks a lot!
Marco

Hi Marco,
did you use the shell command (see photo's).
There is no need for a profile.
Make sure to do the filleting on just the half as I had problem trying to fillet after joining.
Cheers
Barry

Yes,

exactly Barry... that face is not squared and it's rotated, so when I copy-rotate the solid, the result is what I've attahced to my post before...
I can't figure out how to solve...
I followed the same yours steps!

Thanks
Marco

Hi Marco,
it looks like you have extruded the half helix square to the angle of the helix and it should be square to the axis.
If this isn't the case please send me your file.
Cheers
Barry

Ok understood...
Thanks.
What about the fillets, now?
I've cutted and reconstructed the surfaces to avoid crossing points and then launched the fillet... but you can see the results... any idea on how to apply correctly it to the model?

Thanks a lot.
Marco

Post your file before fillets!

Normallly you must have the same fillet along all the volume (don't accept the fillet if you want the following possibility)
then free to you after to make any new "variable fillets" during the same session of fillet on some edges!

Pilou... or maybe Frenchy? ;-)
The bottom small fillet is ok... The top one, instead, is just a suface that moi has used as filletting surface, so its another surface! Just delete it and you have the original solid. I left it just to make you know where is the issue.
Here attached you can find the solid without fillet

Thanks.
Marco

Hi Marco,
not sure what your problem with filleting is ?
Do all large fillets first then the small ones.
Attached your test with fillets.
Cheers
Barry

Ps: just found a problem with your large fillet where you have tapered it from front to back you have 3 edges created by the fillets converging at the front so when trying to add a fillet on the front edge no go.
I selected the 3 edges of the top ran 0.7 fillet and second fillet points for a 0.4 fillet at the back and that is what I have posted.
Are you trying to get the side fillets to match the front fillet where they meet at the front ?

Pilou is sufficient! ;)

The file that you send has yet many fillets!
As it's not so speed to erase them will be fine if you have the original without any fillets :)

Remember that you can make very tiny fillets on some places if needing!

Ok Pilou!
Thanks.
This evening I'll see the video... it seems very complete!
So do you think it's fillet-able?

Ok, let me post the original one with no fillets!

Thanks