Engagement Ring Tutorials Part 6a: Create Four Ring Shanks

Create a Thick, Flat Ring Shank

In Part Six of the Engagement Ring Tutorial Series, you will experiment with using different shapes to function as cross-section curves for sweeping ring shanks.

Over the course of this tutorial, learn to create four different ring shanks -a thick and flat band; a thin and flat band, a tapered band, and a knife-edged band. Once complete, these shanks can be combined with the settings created in this series to form a completed engagement ring.

Get started with this first part of the tutorial and create a simple thick, flat band.

Key Rhino Learning Points/Commands: Layer Manipulation, Shape Creation, Fillet, Sweep 1 Rail, Mirror, Copy, Gumball Manipulation.

Pre-Requisite Knowledge: Basic navigation, Layers, Viewport manipulation, Ortho, OSNAP’s.

Let’s get started!

Check out the master-page list for all tutorials in this series here:

Introducing a new tutorial series- Creating an Engagement Ring in Rhino 3D

This diagram details the dimensions of the ring shank you will create:

Start by opening Rhino. Use the template option: Large Objects — mm to give enough room to work with, and view the objects created in this tutorial.

1. Open a new model in Rhino CAD.

2. Use the option Small Objects — mm.

3. Save your project to the default Rhino as 4_shank_templates.3dm

Organize your layers. Since this is a larger project, we will be using more layers, and organization will allow for ease of use, and any future changes necessary.

1. Create the following layers: Cons Lines, Ring Shank 1, Ring Shank 2, Ring Shank 3 and Ring Shank 4.
2. Right click on the Cons Lines layer, and select the Create New Sublayer option. Name the new sublayer Cons Lines 1. Create two further sublayers -Cons Lines 2, Cons Lines 3 and Cons Lines 4.
3. Change the colors of each Cons Lines Sublayer and the Ring Shank Layers so they match. In this case, I used a darker version of the same color between Cons Lines 1 and Ring Shank 1, for example. This will help keep your project organized.
4. Delete any unused layers.

Create the construction lines for the ring size. For this tutorial we will be using a size 8 ring size with a diameter of 18.14 mm. Feel free to substitute your appropriate ring size.

Refer to this ring size chart:

Ring size — Wikipedia

1. Go to Front view.
2. Ensure the Cons Lines layer (not any of the sublayers created earlier) is selected.
3. Enter the circle command.
4. Center of circle: Input 0. Press enter.
5. Diameter: Input 18.14 (or size-appropriate diameter). Press enter.
6. The construction circle representing the ring size will be placed on the workplane.

Create the construction lines for the first ring form -a thick, flat band. You will use two rectangles to create a band that is thinner at the bottom, gradually thickening towards the top.

1. Ensure the Cons Lines 1 sublayer is selected.
2. Go to Right View. Ensure Quad OSNAP is selected.
3. Enter the Rectangle command. Select the Center option.
4. Center of Rectangle: Snap to the bottom Quad point of the ring circle.
5. Other Corner or Length: Input 3. Press enter.
6. Width: Input 2. Press enter.
7. The rectangle will now be centered on the Quad point of the circle.

The rectangle will need to be moved to align the top Midpoint of the rectangle with the bottom Quad point of the circle.

1. Ensure Midpoint and Quad OSNAP’s are selected.
2. Enter the Move command.
3. Select objects to move: Select the rectangle. Press enter.
4. Point to move from: Snap to the top Midpoint of the rectangle.
5. Point to move to: Snap to the bottom Quad point of the circle.
6. The rectangle will now be aligned to the bottom of the circle.

Fillet the corners of the rectangle to result in a smoother profile curve.

1. Zoom In to the rectangle.
2. Enter the Fillet Corners command.
3. Select polycurves to fillet: Select the rectangle. Press enter.
4. Fillet radius: Input 0.3. Press enter. You can experiment with different fillet radii to find a shape to your preferences.
5. A nice rounded rectangle will now be on the workplane.

Copy the rectangle to the top of the circle.

1. Zoom out, to see the whole circle construction line.
2. Enter the Copy command.
3. Select objects to copy: Select the rounded rectangle just created. Press enter.
4. Point to copy from: Snap to the Midpoint at the bottom of the rectangle.
5. Point to copy to: Snap to the Quad Point at the top of the circle. Press enter to end the command.
6. A copy of the rectangle will be placed at the top of the circle.

Use the Gumball to widen the copied rectangle.

1. Ensure the Gumball is turned on.
2. Click on the copied rectangle. Select the small RED square to the left on the gumball widget.
3. Scale factor in the X-direction: Input 1.5. Press enter.
4. The rectangle will now be larger to create the widening of the ring shank.

Use Sweep 1 Rail to form the shape of the ring.

1. Go to Perspective View. Ensure the Ring Shank 1 layer is selected. Ensure Midpoint OSNAP is selected.
2. Enter the Sweep 1 command.
3. Select Rail: Select the circle construction line.
4. Select cross-section curves: Select the two rounded rectangles. Press enter.
5. Drag seam point to adjust: Ensure you drag the seam points to the Midpoint OSNAP of each rectangle, where they meet the Quad points of the circle. If you do not, the following undesired result will occur:

Note the results when the seams are not adjusted!

The wonky and twisted result. We don’t want this!

Note the positions of the seams here -this is the correct way to adjust.

Finish off the Sweep.

1. Ensure Style is set to Freeform.
2. Select the Closed Sweep option. Press enter or Sweep.
3. The thick and flat band is now complete!
4. Feel free to experiment with different sized rectangles for sweeping, keeping the band as thick or as thin as you like.

Check out the next tutorial in this part: Engagement Ring Tutorials Part 6b: Create a Thin, Flat Ring Shank here:

Engagement Ring Tutorials 6b: Create Four Ring Shanks