Sorry if this has been covered before.
1. I can not work out a method to create the ring shape with closed ends? (Or to close the ends)
2. From other fiddles I have been doing this morning, if I had the ends closed the shape would not accept any fillet?

Appreciate ideas.

Hi Brian, the problem here is your curve on the front side was not completely closed, it was actually had a small opening where 2 segments were not completely aligned end-to-end:








To tune this up, select the curve and use Edit/Separate to break it into segments, then turn on control points for one of those segments in the problem area, and drag its end so that it snaps directly on to the other segment's end making a fully closed connection. Then select the segments and use Edit/Join to glue them back together.

Then with a fully closed outline your shape should get capped.

- Michael

Thanks Michael.
I was "meticulous" in joining each piece one at a time and making sure that the "join" was ok before I went on adding the next curve. Well thats the method I used!
If found, with extreme difficulty, a couple of other "funnies"

However, at this further stage along, I still am still puzzled at how I might get, at least some fillits on the ring?

Hi Brian, there are still some irregularities with the shape that are causing problems.

Here's another one - there is a tiny slivered fragment in this area:







You must have had a really tiny segment in your original curves there.

Another thing that I noticed is that the arcs on the inside bottom part are not tangent with the body of the ring, there is a pretty shallow angle in there, and actually it looks like there is another tiny surface fragment in that area, it is probably having difficulty making a corner in that area.

When I zoom in closely on the front view I can also see that your ring has a very slight shift to the right, the profiles were not aligned precisely - I would normally recommend doing an extrude to make a shape like this since that guarantees a very precise alignment along the extrusion direction. Here it looks like you must have done a loft between 2 different curves and at some point there was a bit of drift when you moved the second curve back.

I'll see if I can create a tuned up version.

- Michael

Thanks Michael. I found them all. eventually. Very, very close up to find some of those wierd ones.
I hope I will remember to do more ,in depth!, analysis.

Actually the one arc on the lower inside is ok - it is an arc in the upper-left corner that is not quite tangent to the line it is next to, it comes within 1.5 degrees of being tangent.

Things that are very close to being tangent but just a small amount off tends to be problematic for the filleter, it will see it as a sharp corner and try to construct a fillet corner piece there which will be microscopic and tend to gunk things up.

So another tune up is to get those arcs and lines to be trued up instead of slightly off.

- Michael

Hi Brian, I've attached a tuned up version of the profile curve here - I fixed some of the tangent alignment problems by turning on control points and using Transform/Align to make sure that points between segments that were only very close to being tangent were trued up to be exactly tangent.

This was basically selecting sets of points that looked like they should be lined up horizontally or vertically but were just slightly off - then align can make them all be straightened out.

You can now extrude this profile (attached as RingTry_tuned.zip), then cut it and the result can be filleted properly:



You can go up to about a 0.4 radius fillet before there isn't any room left at the very bottom part of the ring.


It would be nice if you didn't have to worry about any of this, but the filleter is sensitive to any kind of irregularities at all.

Maybe I can tune this up a bit inside Join or something, to true up tangents between joined pieces if they are within 3 or 4 degrees of each other, that might help. I have made a note to myself to investigate doing some automatic cleanup like this in the future.

- Michael

You are very good Michael. I had solved it all--but a very slow process. No doubt a refing of the workings as you suggest sound good.

Hope you like my end result efforts. (Carrara6Pro)

And another ring just for fun.