Engagement Ring Tutorials Part 6d: Create Four Ring Shanks

Create a Knife-Edge Ring Shank

Continue with the Engagement Ring Tutorials Part 6, as you use different cross-section curves to create a tapered ring shank in this tutorial.

Check out the first part here:

Engagement Ring Tutorials 6a: Create Four Ring Shanks

The second here:

Engagement Ring Tutorials 6b: Create Four Ring Shanks

And the third here:

Engagement Ring Tutorials Part 6c: Create Four Ring Shanks

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

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

Let’s get started!

Check out the master page of tutorials in the ring shank series here:

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

Here is the diagram detailing the ring shank you will be creating in this tutorial. The band will taper to an edge where the stone will eventually sit -this allows for more focus on the center stone of a ring. This kind of band is well suited to solitaire engagement rings.

In this model, I have created a fairly subtle knife edge, that flows into the flat portion of the shank. If you want to create something sharper, feel free to experiment with different shapes to sweep the ring band as you follow along through the tutorial.

Open up the ring shank template file created in the first part of this tutorial, and begin organizing your project before you create the ring.

1. Open up the file created in the first part of this tutorial: 4_shank_templates.3dm.
2. Turn off layer visibility for Cons Lines 1–3 and Ring Shank 1 -3. Layer visibility for Cons Lines 4 and Ring Shank 4 should be the only ones turned on.
3. Ensure the Cons Lines 4 layer is selected.
4. Only the ring-circle construction line should be present on the workplane.

You will need to create three shapes to form this ring shank — a rounded rectangle at the bottom, a larger rounded rectangle at the mid-quad point and a rounded pentagon for the top portion of the shank. Let’s create the rectangle at the bottom first.

1. Ensure Midpoint and Quad OSNAP’s are selected. Go to the Right viewport.
2. Enter the Rectangle command. Select the Center option.
3. Center of rectangle: Snap to the bottom Quad point of the ring construction line circle.
4. Other corner or length: Input 2. Press enter
5. Width: Input 2. Press enter.
6. Using the Move command, move the rectangle from top Midpoint Snap to the Quad Snap at the bottom of the ring construction line circle.

The width of the ring will gradually enlarge towards the top of the ring shank. Make a copy of the rectangle to the mid-Quad point of the ring construction line circle, that will be widened in the following steps.

1. Enter the Copy command.
2. Select objects to copy: Select the rectangle just created. Press enter.
3. Point to copy from: Snap to the top Midpoint of the rectangle.
4. Point to copy to: Draw the cursor up, until you hit the Quad snap of the ring construction line circle (near the middle). Press enter.

5. Go to the Perspective viewport. Turn on the Gumball widget.

6. Select the rectangle just copied, and select the green curve, to rotate along the Y-axis.

7. Angle to rotate on the y-axis: Input 90. Press enter.

8. With the rectangle still selected, use the Move command to move the rectangle from its left-most Midpoint to the Quad point on the ring construction line circle.

Widen the width the rectangle just copied to 2.5mm using the Gumball.

1. Ensuring the Gumball widget is still turned on, select the rectangle just copied.
2. Select the green square representing the scale handle along the Y-axis of the Gumball.

3. Scale factor in the Y-direction: Input 1.25. Press enter

4. The rectangle will now have a width of 2.5mm.

Make a copy of the rectangle and rotate into place on top of the ring construction line circle.

1. Ensure the Gumball, Midpoint and Quad OSNAP’s are turned on.
2. Use the copy command to copy the rectangle from its midpoint where it touches the ring construction line circle, to the top Quad point of the ring construction line circle.

3. Keeping the rectangle just copied selected, use the green arc on the Gumball widget to rotate the rectangle.

4. Angle to rotate around the y-axis: Input 90. press enter.

5. Use the Move command to move the rectangle from its bottom Midpoint back to the top Quad point of the ring construction line circle.

Use control points to create a pentagon with the same height as the rectangle.

1. Zoom in, to get a better view of the top rectangle.
2. Enter the PointsOn command.
3. Select objects for control point display: Select the top rectangle. Press enter.
4. Reduce the height of the rectangle using the control points. Select the top two control points, using a window select.
5. When the Gumball widget appears, click on the blue arrow to move the points in the direction of the Z-axis.
6. Direction to move in the Z direction: Input -1. Press enter.

Add a control point to the top of the rectangle you just reduced in height.

1. Ensure Midpoint OSNAP is selected.
2. Enter the Insert Control Point command.
3. Select curve or surface for control point insertion: Select the top rectangle.
4. Point on curve to add control point: Snap to the top Midpoint of the rectangle.
5. Press enter to end the command. You will now be ready to turn the rectangle into a pentagon.

Move the control point upwards to create a pentagon.

1. Select only the control point you just created, ensuring the Gumball is turned on.
2. Select the blue arrow on the Gumball widget, to move in the Z-direction.
3. Distance to move in the Z-direction: Input 1. Press enter.
4. You will now have a pentagon on the workplane. Press Esc to turn off the control points.

Round the corners of all the shapes so your ring will have a nice, smooth profile curve.

1. Enter the Fillet Corners command.
2. Select polycurve(s) to fillet: Select the rectangles and the pentagon. Press enter.
3. Fillet Radius: Input 0.3. You can also play around with a few different values, to see which you prefer. Press enter, and your shapes are ready to create the ring shank.

Use the pentagon and lower rectangle to split the ring construction line circle. This will make it easier to form the correct shape for the shank.

1. Enter the Split command.
2. Select objects to split: Select the circle. Press enter.
3. Select cutting objects: Select the pentagon and lower (smaller) rectangle. Press enter.
4. The ring construction line circle will now be split in half

Form the shank using Sweep 1 Rail.

1. Enter the Sweep 1 Rail command.
2. Select rail: Select the right-most curve of the circle you just split.
3. Select cross section curves: Select the two rectangles and the pentagon. Press enter.
4. Drag seam point to adjust: Align the seams so they hit the Midpoint OSNAP of each shape where it touches the curve of the split circle. Ensure all arrows point in the same direction. Press enter.

If your seams do not align properly, you will have a twisted shape.

5. Select the Refit within 0.01 option in the pop-up dialog box. All other options can remain as their defaults. Select sweep. Half the ring shank will be created.

Mirror the half shank to the other side, and complete the ring.

1. Go to the Front viewport. Ensure Ortho is turned on.
2. Enter the Mirror command.
3. Start of mirror plane: Input 0. Press enter.
4. End of mirror plane: Draw the cursor straight down and click when the shapes align.
5. Enter the Join command.
6. Select objects to join: Select one half of the shank.
7. Select surface or polysurface to join: Select the other half of the shank.
8. Your knife-edged ring shank is now complete! Experiment with using different shapes for your sweep -such as smaller or larger rectangles, or pentagons with a more exaggerated top vertices, to get a shank to your liking.

You now have four completed ring shank templates to use for your projects. Turn on visibility for Rings Shanks 1–3 to see them all!

Use the techniques you learned creating these four ring shanks, as well as the tutorial Combining the Ring Shank and Basket to combine settings and shanks for a custom, diamond solitaire ring. Happy designing!