Hi Hans - well, the truth is, I did not make that particular area very cleanly in my model, that is, the surfaces there were not checked for tangency- mostly I was trying to give you an approach, but you still need to pay attention; I’ll take a look at how that might be fixed up.
RingCutout_PG-Cleanup.3dm (1.9 MB)
-Pascal
Manually it can be achieved but a fair amount of back and forth.
IMO; The angularity of where the surfaces intersect becomes one of the factors that throw this sideways.
But, if you extend the surfaces past your mitered corner
then fillet the primary edges 1st then you can manually trim the intersects and you are left with the deep corner void(six-sided hole). This can be a patch.
Some reworking needs to happen to ensure no naked edges.
But achievable
Hi Pascal,
What was the approach you took to achieve tangency with those faces? Did you take the faces in your first step, duplicate the inner edge of the outer shapes, trim that edge where the horizontal planes met it, and then match surface the edge of the inner shape to the newly generated curve?
Here’s where I’m at right now, I tried to carefully follow along with @pascal’s advice and started from scratch by:
expanding the vertical planes on my original model ring to cut through an extruded cross section of the ring made by projecting it’s outline to the front c plane and then extruding.
I then trimmed the vertical planes so that they we’re between the outer and inner edge of the ring cross section. I then re-created the length ways supports so that they were tangent with the side of the ring faces and trimmed those as well.
I created planes at the ends of the ring shank to cap off and trim the vertical planes at their ends.
I created, and trimmed the planes for the horizontal supports for the side stones so that the planes were between the inside and outside edges of the cross section extrusion.
I trimmed the cross section extrusions to size.
I joined the faces to create a closed solid polysurface and then proceeded to fillet the curves on the object. This was my closest attempt yet but still has problems on multiple corners/edges…
6Stages.3dm (6.0 MB)
I’m not going to go any further but the two surfaces causing this fillet corner to be so complicated could be rebuilt with a single surface.
dear @Hans_Hartle
i agree with @martinsiegrist that you ll have less problems with the outer surface / corner if you bild it in one go - i am thinking of another initial surface:
you will still have some issues regarding the inner 6-side corner (x)
so i would recommend to handle the pink and green surface in the same way
this remaining corner (x) will not be able to fillet with a _filletEdge
the reason are the angles of the surface that make the command fail:
6-side-corner rectangular
from left to right
(1,2) rectangular
works but the solution does not respect symmetry / inside / outside - the inner sphere is not obvious
(3) steeper angles but still planar surface
typology gets more complex and some self-intersections occure (x)
(4) even more steeper angles and curved surfaces
fail.
6-side-corner_02.3dm (4.8 MB)
there was a intense discussion on this kind of problems here
maybe @pascal can tell if there is any news on this issue.
Quadremesh >>> SubD 
It needs some cleaning and could of course be done with less definition.
Could be a starting point.
subd_ring.3dm (1.2 MB)
Hey @Tom_P and @martinsiegrist,
Can’t say enough how much I appreciate your help. Sorry for not posting an update last night, but I ended up with a result and process that was fairly similar to both of yours!
Following along with @martinsiegrist suggestion to rebuild the 3 outer surfaces into a single surface, I decided to combine all of the vertical extrusions (the legs of the shank and the length ways supports) into 4 surfaces. Unfortunately I didn’t make a save at this step (I should have) but I poorly colored in one of my saves, after those 4 surfaces had been trimmed so you can get an idea:
As both of you mentioned and Pascal alluded too, having singular surfaces before trimming for the inside/outside of the shank’s legs made the fillet significantly less complex.
I did this by taking the two existing surfaces by color, duplicating their edges, deleting the surfaces. connecting the inside corners of the two edge loops together and then using NetworkSrf. Not sure if there is a better way but this worked really well for me.
After I needed to add the horizontal supports for the side stones in, and like you mentioned @Tom_P the six sided corner was not working. I appreciate the walk though, it’s definitely falls into the category of we know how it should look but it’s not easy to compute.
I settled on shifting the horizontal support down and the result is incredibly similar to Martin’s. I’ll attach a side by side here (Martin’s on the left, mine on the right):
One of the main differences was I decided to leave the inside vertical edges un-filleted because it looked better in the render, although I’m not sure if that’s feasible when casting / 3d printing.
CompMartinHans.3dm (4.1 MB)
Nice @Hans_Hartle !
Will this ring be printed in wax and cast in a sand mold, then sanded / grinded and polished?
Current Idea is to have this be 3d wax resin printed in order to be sent to a casting house for casting, sanding, grinding, and polishing. The casting house I was planning on working with uses lost-wax casting but doesn’t say if they use a sand or rubber mold.
Thanks for the info. I’m not familiar with the radii typically applied on jewelry. I just think it’s an overkill to spend hours on fillets when the end result is sanded and grinded. I think a SubD is easier to edit than the surface based model with fillets.
