“I think engagements are an opportunity to be really creative.”
-My fiancee

So you’ve found the love of your life, and you’re ready to pop the question, what now? Well, if they have issued the challenge above, then you better get creating! My girlfriend posed this challenge almost a year ago, and I’m happy to say, that with the help of Dynamo, I got to be really creative and got the response we all look for when we get down on one knee.

At AU2016 I took a class about the experimental set of nodes for T-Splines. Ronnie Parsons taught a class at AU called Dynamo: Generative Modeling with T-Splines. Ronnie said something that stuck with me, essentially that T-Splines are inherently construct-able geometry; watertight and 3D printable by default. For anyone who’s spent time with meshes, this is a dream come true.

T-Splines were introduced in Dynamo 1.1, but to me, they were essentially a mystery. Frankly, they’re still are a bit of a mystery, but in a single, beginner level graph, he showed me the tools that would start me down the path of designing the engagement ring in dynamo.


To read more about T-Splines T-Splines in Dynamo.

These 4 lines had been instantly transformed into elegant, organic forms, and I was sure that if I could conceive of the basic pattern for the design, then Dynamo and T-splines would take care of the rest… how little I knew.

The key was to get a set of lines that would be the core of my design. All subsequent form would be based on the curves I created. To start the design process I essentially started sketching in Revit, drawing nurbs and swoops and arcs looking for the right shapes. Finally, I decided to draw inspiration from the Fibonacci Sequence. Not only is the Fibonacci sequence often found in nature, but the ratio of adjacent Fibonacci numbers converges to the golden ratio.


Fibonacci spirals and squares in the fibonacci ratio form the base of the design

From my sketches in Revit, I needed to get that geometry into Dynamo, and get the geometry into some sort of 3D ring like shape. Fortunately getting geometry from Revit to Dynamo is trivially easy.

The issue of putting this form to be ring shaped was more of a puzzle. The final strategy was getting a list of points of the design curves, and then “wrapping” them around an underlying ring form. I visualized laying my design down on the edge of a circle. If the design started out centered on the circle, then the distance from the center would end up being the distance along the circle.

The wrapping is taking the X value of the points, and turning that into a distance from the center, along the ring, finding the point there, and using those points’ X and Z coordinates. To keep the design shape I use the original Y coordinate to make new points. These points then served as the basis for rebuilding curves that followed the shape of the ring.


T-Splines turn curve geometry into wonderful organic forms easily with the Pipes nodes

Now, this process resulted in a pretty cool design, but my proportions were clearly all wrong, I’d made a ring for a Giant!

First print… woops, good thing it’s all parametric

I liked my idea, but I needed help, which meant I needed a jeweler. A friend recommended someone who specialized in custom rings. Serjeo was an amazing help, and with his guidance I got back to my nodes and wires to add the shape for a more substantial form and to hold diamonds.

The goals were to re-size, add thickness to the entire band, and add more dimension. The “pipes” needed to be a larger diameter, which was a simple change. Making the ring able to hold a diamond meant manipulating the main body of the design to make use of t-spline surfaces rather than pipes. The curved and square regions were extruded to form surfaces that could be made into T-Spline surfaces giving the entire top of the ring much more depth.


New design guidelines, gotta build up more form. In keeping with my desire to understand T-Splines, I used a T-SplineSurface.Thicken node. My strategy for getting these walls was then to build a surface where I wanted the wall to be, and then thicken it in the direction I wanted. The result was smooth, swooping walls.

Now, this more complicated design needed to be exported for 3D printing. The first ring was super easy to export, but this geometry was made of multiple different forms which I wanted to blend together. These forms did not merge into a single mesh nicely, with too many intersections and vertexes within other solid forms. Through trial and error I landed on a process of converting sections of the overall design into into BREP geometry, joining these, and only then exporting a mesh. The final form wasn’t perfect, but it was enough that I went ahead and printed another test ring, this time in plastic.


New print, that’s my pinky, still the wrong size, but we’re getting there

Closer, but now I needed to increase the size to adjust for the increased pipe diameter, which I hadn’t thought of. This meant a few more tweaks and preparing for the real print. My T-Spline technique had left some gaps in the mesh which I cleaned up using Mesh Mixer https://www.meshmixer.com/. This free Autodesk tool took no time to learn and was truly amazing. A combination of smoothing, bulging, and re-meshing resulted in nice clean seams between all my separate T-Spline forms.


Mesh all cleaned up, the heart is just there for dramatic effect, it wasn’t part of the final mesh.

This model was then 3D printed in wax, which was used to make the final ring. Once cast in white gold Serjeo made changes to the ring’s profile and set in diamonds.

The final touches were underway, all that was left was a proposal. A trip to South Africa presented beautiful opportunities, and so, even though the ring wasn’t quite done, I proposed there, using a picture of the ring with its diamonds. She said yes, and then, because it was all still being custom made, my fiancée got to have input in some of the final design.
All in all, it was an immensely satisfying project, a great learning experience and a great excuse to learn T-Splines for a one of a kind design.


Happily engaged after a sunrise hike. Lion’s Head Mountain in the background.