Learn How to Make Twists in Rhino 3D -Create a Torque Style Cuff Bracelet

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Jewelry Design with Rhino 3D

Now, let’s get back to the lesson!

Learn how to create a twisted wire style torque bracelet in Rhino. Practice working with Polar Arrays, Twists, Arcs and custom Curves as you work through this tutorial. Once complete, you will have a good understanding of how to apply these commands and concepts to future Rhino projects.

Key Rhino Learning Points/Commands: Ellipse, Polar Array, Fillet Curve, Join, Trim, Twist, Arc, Curve, Revolve, Cap, Flow, Gumball manipulation, Length calculation, Mirror

Pre-Requisite Knowledge: Basic navigation, layers, perspective and viewport manipulation, basic shape creation, Ortho and OSNAP’s.

Start by opening Rhino and using a template. Let’s use the option: Large Objects — mm to give us enough room to work and easily view the objects created in this tutorial.

1. Open a new model in Rhino CAD.

2. Use the option Small Objects — mm.

Create layers to organize your project. Delete any unused layers.

1. Create the following layers, as named in the image below:
2. Delete any unused layers

Since this bracelet will be an open-cuff style, it will not form a perfect circle like a bangle might. Use an Ellipse to form the shape for the bracelet construction lines.

Typical cuffs are usually around 7 inches in length -less a 1-inch gap opening. We will use the following measurements:

• Total cuff length: 166.25 mm
• Gap Length: 25.4 mm

1. Select the Bracelet Cons Lines layer.
2. Ensure Ortho is turned on.
3. Go to Front view.
4. Enter the Ellipse command.
5. Center of Ellipse: Enter the coordinates 0,0,-75. Press enter. The ellipse should be placed further back on the Z-plane in order to keep objects orderly and easy to visualize.
6. End of First Axis: Input 27.5. Press enter. Draw the cursor straight up and click.
7. End of Second Axis: Input 32.5. Press enter. Draw the cursor to the right and click.
8. You will now have an ellipse forming the bracelet construction line.

Place a Point object as a reference for trimming the cuff-gap.

1. Begin this process by placing a Point object at the bottom of the ellipse.
2. Ensure Quad OSNAP is selected.
3. Enter the Point command.
4. Location of Point Object: Snap to the Quad point at the bottom center of the ellipse.

Form the reference lines for where the shape will be trimmed.

1. Ensure Point and End OSNAP’s are selected.
2. Ensure Ortho is turned on.
3. Enter the Line command.
4. Start of Line: Snap to the Point object created in the previous step.
5. End of Line: Input 12.7 (half of the distance for the gap in the cuff), press enter.
6. Create a second, vertical line. Enter the Line command.
7. Start of Line: Snap to the End point of the line just created.
8. End of Line: Draw the cursor straight up, through the bottom of the ellipse.

Use the Mirror command to copy the lines to the other side of the ellipse.

1. Ensure that Point OSNAP is selected.
2. Ensure Ortho is turned on.
3. Enter the Mirror command.
4. Select objects to mirror: Select the two lines just created. Press enter.
5. Start of Mirror plane: Snap to the Point at the bottom center of the ellipse.
6. End of Mirror plane: Draw the cursor straight downwards and click, so the lines are mirrored (copied) to the other side of the ellipse.

Trim out the gap in the ellipse using the guidelines just created.

1. Enter the Trim command.
2. Select cutting objects: Window select the guidelines and the ellipse. Press enter.
3. Select object to trim: Click to trim away the curve of the ellipse between the vertical lines as well as the guidelines, which are no longer needed.
4. Press enter to complete the command. An ellipse with a gap cut out will form the cuff-bracelet construction lines.

Measure the length of the gapped-ellipse.

1. Enter the Length command.
2. The length of the ellipse will be shown (in mm) at the bottom-left corner of the interface. Take note of this amount.

Turn off the Bracelet Cons Lines layer visibility to maximize visibility in the following steps.

Create a circle that will serve as the base-form for the shape we will be twisting.

1. Select the Twist Cons Lines layer.
2. Go to Front viewport.
3. Enter the Circle command.
4. Center of Circle: Input 0. Press enter.
5. Radius: Input 3. Press enter.
6. The first circle will be created.

Create a reference line to copy the circle using the Array Polar command in the next step.

1. Ensure Quad OSNAP is selected.
2. Ensure Ortho is turned on.
3. Enter the Line command.
4. Start of Line: Snap to the Quad point on the bottom of the circle.
5. End of Line: Input 1. Press enter.
6. Draw the cursor down and click.
7. A short line will form the reference point for the next step.

Use the Array Polar command to create copies of the circle

1. Ensure End OSNAP is selected.
2. Select the circle just created.
3. Enter the Array Polar command.
4. Center of Polar Array: Click on the End point of the line created in the previous step.
5. Number of Items: Input 6. Press enter.
6. Press enter to accept the defaults for the following options.
7. Six copies of the circle will be arrayed around the End point of the reference line created in the previous step.

You might wish to experiment on using more or less circle copies to change the look of the twist that will be created.

Add curves between the circles using the Fillet Curve command to give a nicer shape to the twist.

1. Zoom in on the top two circles.
2. Navigate Curve > Fillet Curve.
3. Radius: Input 0.5. Press enter.
4. Select first curve to fillet: Select the first circle created, close to its boundary with the circle to the immediate left.
5. Select second curve to fillet: Select the circle to the immediate left of the circle selected in Step 4.

Use this image as a guide for where to click and select the curves to Fillet.

6. A smooth curve will be formed between the circles.

Use the Array Polar command to copy the curve just created for each circle.

1. Ensure End OSNAP is selected.
2. Enter the Array Polar command.
3. Select objects to array: Select the filleted curve created in the previous step. Press enter.
4. Center of polar array: Snap to the End Point at the bottom of short reference line.
5. Number of items: Input 6. Press enter.
6. Press enter to accept the defaults for the following options.
7. Copies of the filleted curve will be arrayed around each circle.

Use the Trim command to create a single curve object of all the shapes.

1. Enter the Trim command.
2. Select cutting objects: Use a window select to select all circles and curves. Press enter.

3. Select object to trim: Trim off all overlapping lines and curves. Zoom in and out as needed.

4. Press enter when complete. The remaining curves should look like a flower shape.

Use the Join command to merge all curves into one object.

1. Enter the Join command.
2. Select object for join: Select all curves.
3. You will now have one closed curve object.

Rotate the flower shape and the small reference line along the Z-axis. This step will be accomplished easily using the Gumball.

1. Go to Perspective view. Zoom in as needed.
2. Ensure the Gumball is selected.
3. Window-select the flower-shape and small line.
4. Click on the blue Gumball Z-Rotation curve.
5. Angle to rotate around the Z-axis: Input 90. Press enter.
6. Your objects will now be rotated.

Create the twist flat construction line. Use the following measurements

• Bracelet length: 166.26 mm
• End cap length (x2): 27.6 mm
• Twist flat length: 138.66 mm

1. Go to Top Perspective view. For a refresher on using all viewpoints in Rhino, refer to my previous tutorial Create a Basic Ring Using Rhino Cad (step 6) for instructions.
2. Ensure End OSNAP is selected.
3. Ensure Ortho is turned on.
4. Enter the Line command.
5. Start of Line: Snap to the End point at the bottom of the reference line in the center of the flower shape.
6. End of Line: Input 138.66. Press enter.
7. Draw out the cursor straight to the right, and click on the workplane.
8. The twist construction line will be complete.

Extrude the flower shape.

1. Select the Twist Flat layer.
2. Ensure End OSNAP is selected.
3. Go to Solid > Extrude Planar Curve > Straight.
4. Select curves to extrude: Select the flower shape. Press enter.
5. Extrusion distance: Snap to the End point of the construction line.
6. The extruded shape will now form a solid object on the workplane.

Use the Twist command to transform the extruded shape.

1. Ensure End OSNAP is selected.
2. Enter the Twist command.
3. Select the extruded object. Press enter.
4. Start of twist axis: Snap to one end of the Twist Flat Construction line.
5. End of twist axis: Snap to the other end of the line.
6. Angle or first reference point: Ensure the Infinite option is selected (or the twist will not extend to the edges of the shape). Input 1800. Press enter.
7. The extrusion will now be twisted.

The twisted extrusion viewed in Rendered display mode.

Create the reference lines for the end caps of the cuff.

1. Turn off the Twist Flat layer visibility using the small lightbulb to the right of the layer name.
2. Ensure the Twist Cons Lines layer is visible.
3. Select the Cap Cons Lines layer.
4. Ensure End OSNAP is selected.
5. Ensure Ortho is turned on.
6. Go to Front view.
7. Enter the Line command.
8. Start of line: Snap to the End Point on the left side of the Twist Flat Construction Line (where the flower shape curves are located).
9. End of line: Input 13.78 (half the value of the cap length, noted above). Press enter.
10. The construction line for the cap will be formed (in purple).

Create a cylinder. This step will make use of switching views mid-command.

1. Select the Cap Flat layer.
2. Go to Top Perspective view.
3. Ensure End and Midpoint OSNAP’s are selected.
4. Input the Cylinder command.
5. Base of cylinder: Snap to the End Point on the right side of the construction line created in the previous step.
6. Switch to Right view.
7. Radius: Draw the cursor out to the top of the flower-shaped construction line for the twist extrusion until the Midpoint OSNAP appears. Click the cursor.
8. End of Cylinder: Input -5 (ensuring the cylinder extrudes to the left). Press enter.
9. The first portion of the cap-piece is complete.

Create the first reference line for teardrop shape of the cap.

1. Select the Cap Cons Lines Layer.
2. Go to Top Perspective view.
3. Ensure Ortho is turned on.
4. Ensure the Intersection OSNAP is selected.
5. Enter the Line command.
6. Start of Line: Snap to the Quad point at the top-left of the cylinder.
7. Switch to Right view.
8. End of Line: Draw the cursor straight down and snap to the Intersection point in the center of the cylinder.
9. A short, straight reference line from the top of the cylinder to the cap construction line will be formed.

Use the Curve command to form the construction line for the teardrop piece.

1. Turn off visibility on the Cap Flat layer.
2. Select the Cap Cons Lines layer.
3. Go to Front view.
4. Ensure End OSNAP is turned on.
5. Start of Curve: Snap to the top End point of the reference line created in the previous step.
6. Next Point: Move the cursor to the left, above the vertical reference line. Use the image below as a guide.
7. Next Point: Snap to the End point of the horizontal reference line. Press enter to end the command.
8. A curved construction line for the next step will be formed.

Use the Revolve command to create a surface from the curve just created.

1. Turn on and select the Cap Flat layer.
2. Go to Top Perspective view.
3. Enter the Revolve command.
4. Select curves to revolve: Select the curve created in the previous step. Press enter.
5. Start of revolve axis: Snap to the End Point of the horizontal reference line at the lower-left end of the curve.
6. End of revolve axis: Snap to the End Point where the vertical and horizontal reference lines for the cap meet, below the right side of the curve.

7. Press enter to accept the defaults for the following two options.

8. A tear-drop shape will be formed.

Close the object created in the previous step using the Cap command. Revolved curves are surfaces, and not closed objects.

1. Enter the Cap command.
2. Select surfaces or polysurfaces to cap: Select the surface created in the previous step.
3. A closed teardrop object will be formed.

Use the Boolean Union command to create a single object from both cap pieces.

1. Enter the Boolean Union command.
2. Select surfaces or polysurfaces to union: Select both pieces of the cap. Press enter.
3. A single object will result.

Use the Mirror command to create a copy of the cap on the other side of the twist.

1. Go to Front view.
2. Ensure Midpoint OSNAP is selected.
3. Ensure Ortho is turned on.
4. Enter the Mirror command.
5. Select objects to mirror: Select the unioned cap piece. Press enter.
6. Start of mirror plane: Draw the cursor to the right and snap to the Midpoint of the horizontal construction line.
7. End of mirror plane: Draw the cursor straight down until the cap piece is copied to the other side. Click to end the command.
8. Two caps will be formed parallel to each other.

Use the Boolean Union command create a single object from the caps and twist pieces.

I find it useful to Copy and Hide objects before I use Boolean Union, in case measurements or designs need to be tweaked at a later point.

1. Turn on and select the Twist Flat layer.
2. Enter the Boolean Union command.
3. Select surfaces or polysurfaces to union: Select the cap-pieces, and the twist.
4. Press enter when done. A single object will be left.

Create a reference line for the Flow command to be used in the following step.

1. Turn off visibility on the Twist Flat layer.
2. Ensure the Twist Flat Cons Lines and Cap Flat Cons Lines layers are visible.
3. Delete or Hide the horizontal reference lines on these layers.

4. Turn back on visibility for the Twist Flat layer.

5. Ensure the Twist Flat Cons Lines layer is selected.

6. Ensure End OSNAP is selected.

7. Enter the Line command.

8. Start of line: Snap to one end of the twist-flat object.

9. End of line: Snap to the other end of the twist flat object.

10. There will now be a reference line for the next step.

Use the Flow command to copy the flat bracelet-object onto the bracelet-construction line ellipse created at the beginning of this tutorial.

1. Turn on the Bracelet Cons Lines layer visibility.
2. Select the Bracelet layer.
3. Go to Top Perspective view.
4. Ensure Wireframe viewing mode is selected.
5. Enter the Flow command.
6. Select objects to flow along curve: Select the flat piece. Press enter.
7. Base curve -select near one end: Zoom in and click near one end of the reference line created in the previous step.
8. Target curve -select near one end: Click at one of the end of the bracelet construction line.
9. Move the resulting shape to the Bracelet layer.

Congratulations! You have completed this tutorial and learned several important skills to utilize in future Rhino 3D tutorials.

The final bracelet viewed in Rendered display mode.