Create a Spiral Earring in Rhino 3D

In this tutorial you will learn how to create an elaborate spiral earring. It may look complicated, but the actual process for creating the earring is fairly simple. Learn how to use commands including the curve tool, revolve and pipe.

Key Learning Points: Curve, revolve, interpolate curve on surface, pipe, gumball, scale 2D.

Pre-Requisite Knowledge: Viewport manipulation, layers, basic shape creation, ORTHO, OSNAPS, extrude solid, torus.

First set up your file using and create layers to keep your project organized.

1. Open Rhino. Choose the default template- Small Objects — Millimeters.
2. Create your layers as shown below. Delete any unused layers.

Create a vertical line to form the reference geometry for the spiral.

1. Go to the Front Viewport.
2. Ensure you are on the Construction Lines layer.
3. Ensure Ortho is turned on.
4. Enter the Line command.
5. Start of line: Input 0, press enter.
6. End of line: Input 20, press enter.

The spiral we will create for the earring needs to flow along the surface of a curved object. To do this, we will use the curve tool to create a free-form curve, and then revolve it to create a solid object.

In Rhino, you can create a curve, and edit it later by adjusting the control points as needed. Either follow the steps below or create your own shape.

1. Ensure that End OSNAP is selected.
2. Enter the Curve command.
3. Start of Curve: Snap to the top End of the line just created.
4. Next Point: Input 12, 2. Press enter.
5. Next Point: Snap to the bottom End of the line.
6. Press enter to end the command.

The curve with control points showing.

Use the Revolve command to create a solid object.

1. Go to the Perspective Viewport.
2. Ensure End OSNAP.
3. Select the curve.
4. Input the Revolve command.
5. Start of revolve axis: Snap to the top End of the line.
6. End of revolve axis: Snap to the bottom End of the line.
7. Press enter twice to accept the defaults for the next two options. You will now have a teardrop shaped object.

Create a curve on the surface of the object.

1. Go to Front Viewport.
2. Ensure End OSNAP is turned on.
3. Go to Curve > Free Form > Interpolate on surface.

4. Start of curve: Snap to the top End of the object.

5. Next point: Draw the cursor down, and click around halfway down from the top.

6. Next point: Turn off the End OSNAP (or you will get an undesirable result). Click towards the bottom of the object. Press enter to end the command.

You now have a smooth curve that will form the basis for the spiral.

Use Array Polar to make 6 copies of the spiral

1. Go to Perspective Viewport.
2. Select the spiral.
3. Enter the Array Polar command.
4. Center of polar array: Input 0. Press enter.
5. Number of items: Input 6. Press enter.
6. Press enter to accept the defaults for the next two choices. You will now have 6 copies of the curve.

The construction lines of the spiral earring shown in Top and Perspective Viewports..

Use the Pipe tool to create solid objects from the construction lines. You can experiment on the thickness of the piped spirals as you like. However, keep in mind you must keep to minimum wall thickness in order to output a successful print. Shapeways requires different thickness depending on the print medium, for instance 0.7 mm for plastic, and 0.6 mm for silver.

1. Select the Spirals layer.
2. Go to Perspective Viewport.
3. Select all the spirals, by either holding down the Shift key and selecting each, or by window selecting the spirals by dragging across them from the right side.
4. Enter the Pipe command.
5. Pipe Radius: Input 0.8. Press enter. You will now have 6 piped spirals for your earring.

Before we can begin creating the top cap for the spirals, two reference lines need to be drawn.

Draw the first line:

1. Select the Cons Lines layer.
2. Ensure End OSNAP is turned on.
3. Ensure Ortho is turned on.
4. Go to Front Viewport.
5. Enter the Line command.
6. Start of line: Snap to the End point of the spirals on the left side.
7. End of line: Drag out the line to the left and click on the construction plane.

Create the second reference line.

1. Turn off the Spirals layer by clicking on the lightbulb beside the layer name.
2. Go to Front Viewport.
3. Enter the Line command.
4. Start of line: Snap to the End OSNAP at the tip of one of the spirals (it doesn’t matter which one).
5. End of line: Drag the cursor upwards and click on the construction plane.

Create a reference circle.

1. Go to Perspective Viewport.
2. Ensure End and Intersection OSNAP’s are turned on.
3. Enter the Circle command.
4. Center of circle: Click on the Intersection snap of the two lines.
5. Diameter: Click on the End snap of the horizontal line.

Extrude the circle to create a solid object.

1. Select the circle.
2. Select the Top Cap/Loop layer.
3. Go to Front Viewport.
4. Go to Solid > Extrude Planar Curve > Straight.
5. Extrusion distance: Input 1. Press enter. The top cap will now be complete.

Turn back on the spirals and view the placement of the cap. If it look a little high, turn on the Gumball and move it down a bit.

1. Turn on the Spiral layer.
2. Turn on the Gumball command.
3. When the widget appears, use the green arrow to drag the cap piece downwards slightly.

Create a loop to attach the spiral to the earring hook.

1. Ensure Near OSNAP is turned on.
2. Enter the Torus command.
3. Center of torus: Hover near the center line drawn earlier until the Near OSNAP appears. Click at this point.
4. First radius: Input 1. Press enter.
5. Second radius: Input 0.3. Press enter. You will now have a loop and have finished off the top piece of the earring.

Copy the cap piece to the bottom of the spiral.

1. Ensure you are still in Front Viewport.
2. Select the Bottom Charm layer.
3. Ensure that Center OSNAP is turned on.
4. Ensure that Ortho is turned on.
5. Select the cap piece.
6. Enter the Copy command.
7. Point to copy from: Hover the cursor over the top cap until the Center OSNAP appears.
8. Turn off the Center OSNAP before completing the next step.
9. Draw the cursor down and click to place the copy at the bottom of the spirals.
10. Press enter to end the command.

Enlarge the bottom cap using the Scale 2D command. Since accuracy is not necessary here, you can experiment with the scale factor to your liking.

1. Go to Perspective Viewport.
2. Ensure that Center OSNAP is turned on.
3. Select the bottom cap.
4. Enter the Scale 2D command.
5. Origin point: Snap to the Center of the cap piece.
6. Scale factor or first reference point: Input 2. Press enter. The cap will now be more proportional to the bottom of the spiral.
7. If you don’t like the placement, use the Gumball command as shown above to move the cap into place.

Create a reference line for the charm piece.

1. Select the Cons Lines layer.
2. Go to the Front Viewport.
3. Enter the Line command.
4. Start of line: Input 0. Press enter.
5. End of line: Draw the cursor downwards and click on the construction plane.

Create a curve that will form the bottom charm.

1. Ensure that End and Near OSNAP’s are turned on.
2. Enter the Curve command.
3. Start of curve: Snap to the End of the cap piece on it’s bottom.
4. Next point: Click to the left of the cap, and start mapping out the curve points. You should try to use only 2–3 points to maintain a smoother shape.
5. The last point should be on the line, where the Near OSNAP appears.
6. Press enter to end the command.

Revolve the curve to finish the earring.

1. Go to Front Viewport.
2. Select the Bottom Charm layer.
3. Ensure End OSNAP is selected.
4. Ensure Ortho is turned on.
5. Select the curve just created.
6. Enter the Revolve command.
7. Start of revolve axis: Snap to the End of the curve just created.
8. End of revolve axis: Draw the cursor up, and click above where the curve begins.
9. Press enter to select the defaults for the next two options and the charm will be complete.

Now the spiral earring is complete. Try viewing it in Rendered display mode to see how it looks.