Solidworks Custom Jewelry

Two and a half months ago, I proposed to my girlfriend Ellie. Since Solidworks played kind of a large part in the process, I thought I'd share the story; I hope you guys find it interesting.

As such a modern couple, we had already discussed marriage, but because I cling to tradition perhaps a little more than she would like, getting a ring and proposing was something I wanted to hold onto. We got a stone from her aunt, which was promised to her as the youngest grandchild. Since I wasn't going to be spending money on a center stone, and since Ellie didn't like the idea of somebody else wearing the same ring as her, we agreed to get it custom made, and as an engineer I wanted to have a lot of control over it.

Ellie had been "helpfully" sending me links to rings she liked so I had some ideas about the style I was going for - light and open - but sturdy enough to handle daily abuse. I wanted to create something that highlighted both Ellie and our relationship. Part of Ellie's family is Irish, and the Celtic symbols are something she's always been a little into, so I liked the idea of making something Celtic-inspired without being too boring and standard. I flipped through a few different sites and came across the triple spiral, which represents various aspects of womanhood; that seemed appropriate, and the spirals had interesting possibilities, so I started sketching (sorry, I took photos of my sketches because the computer with the scanner is temporarily out of commission...)

At this point I had a concept I was really pleased with; a normal person would have taken the sketches to a jeweler but I had other things in mind, so I fired up Solidworks. This was way more complex than anything I do at work, so it was a fun challenge to figure out how to model it. I stayed up several hours after Ellie on at least two occasions because I was enjoying myself too much to quit.
I had played with modeling the simpler open band designs previously, so I had already established that I was going to start with a blank band, and then wrap a flat design around it. I created several helix/spiral features, converted the edges into a sketch, offset, and trimmed. Except...they wouldn't trim. For whatever reason, a sketch converted from a spiral curve can't be trimmed. So instead I converted each spiral into a separate sketch, filled them to create surfaces, then extruded another surface perpendicular to trim their edges and combined all three.

One half of the flat spiral pattern, ready to be wrapped around a band.

I took that and converted its edges back to a new, all-inclusive sketch, and used that to make my wrap. The rest, by comparison, was easy. I wanted the "trunk" that the spirals were branching from to flare out wider underneath, so I trimmed away the band underneath and lofted the shape with a series of profiles and a 3D spline guide. A few fillets and a retroactive scaling to the appropriate size 5 and I was done, in only 40 features:

Views of the completed model; it's not obvious, but on the advice of a co-conspirator, the loft profiles for the interior surface of the band are actually elliptical to allow for an optimal "comfort fit". Since I hadn't even spoken with a jeweler at this point, I hadn't had a chance to become familiar with such terms.

Now, as much as Ellie trusts me, she wasn't willing to let me go ahead and spend a lot of money to get a ring that she might or might not like. We couldn't go to a jeweler to pick out a design, plus I wanted to actually propose for real. What to do? Fortunately, the aforementioned co-conspirator had recently acquired a 3d printer at work, and the small volume of material required for something like this meant that the expense involved in creating a prototype were almost negligible. Less fortunately, the delicate features of the ring were below the resolution of the printer, and the first article fell apart upon removal from the tray. The only option was clearly to scale up the ring, and find a larger woman to propose to.

Ellie with a 2x sized prototype; it's not clear whether she's happy at being proposed to or amused by the enormous ring...either way, she did say yes.

In the end, it turned out that Ellie's lack of confidence in me was unneccessary. She loved the design, and was eager to get it made without changing a thing. After a little searching, we chose a jeweler around the corner in Federal Hill to make the ring, and six weeks after I proposed we picked up the final product:

Getting a custom ring definitely wasn't a simple process; it took longer than I anticipated, but then, I don't think I went about it in the most direct way. Building a computer model of it was a lot of fun and a great challenge of my modeling skills, and it did work out well with the way I ended up proposing, but it really wasn't worth the effort otherwise. The jeweler's source for the casting work wasn't even able to read the 3D file (I sent them a CD containing about every format Solidworks could export), and wound up making the model based on my three-view image above. I would have saved at least a week of sending various file formats back and forth and additional time in various other related pursuits if I'd just taken my sketches in and let them fill in the details. But then we wouldn't have this giant plastic ring and a super-geeky proposal story...