For fun, we sketched a form and sent it out for a 3D print with Shapeways.
With a form that is simple for us to make, we wanted to share the process of designing this step by step to help others learn Rhino and 3D printing as a tool for creation.
After creating the form, our friends mentioned it looks like a contemporary Vajra. So we went with it.
Also, they requested a tutorial on how to make it. So here it is.
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Step 1: Software
The first thing you with need is Rhino3D. Which is available in beta version for Mac for free here.
Step 2: Software and Design Rules
Shapeways: Design Rules
Take a quick look at the design rules for different materials. This will help you engineer your design so that mistakes are not made in bounding area and thickness later.
Max bounding box: 762 × 393 × 393 mm
Min supported wires: 1mm (less than 76mm) / 2mm (less than 152mm and 202mm)
Step 3: Modeling in Rhino
Draw a Rectangle to define the boundary of the form.
*This in not rocket science
We like to model by using the command prompt and typing in the words but we will also show the icon interface to help you to learn the tools.
1. We want to create a bounding box for our deign. Click on the Rectangle icon or type "rectangle" + enter
2. Options in the prompt will allow you to click "center" or type "C" + enter
3. Type "0" + enter and the box center will start on the center of the grid
4. The size we are working with is 400mm long x 45mm height. Type "400" + enter then "45" + enter
Step 4: Curve Modeling
1. Using the curve tool icon or by typing "curve" + enter, draw a curve resembling a fading sine wave from "0" to the right midpoint in about 6 points.
*You can readjust the points later by clicking the curve and using the points on icon or type "Pon" and clicking and moving the points into place.
Step 5: Offset Curve and Close Shape
1. Type "offset" + enter or in the dropdown menu curve / offset / offset curve
2. The prompt will ask you for the value. We are going to offset by 2mm for safe measure. Type "2" + enter
3. Click to the top of the curve for offsetting in the direction
4. We need to close the shape so that we can make a surface in the next step. So draw two lines by typing "line" + enter or use the line icon, one at 0 up to the offset curve, and another at the end
5. The form is not closed. The fastest way I have learned to close and join a shape is by using the Fillet tool.
In the prompt: Radius = 0; Make sure Join and trim are checked. Click near the endpoints of the two lines you want to connect.
*You can delete the bounding box we created if it gets in your way. or "Hide" it. or put it on another layer.
Step 6: Extrude Shape
1. Click on the closed shape and in type "extrude" + enter or in the dropdown menu Solid / extrude from planar curve / straight
2. In the prompt, both sides and solid should be click. Value = 1 *Because we have both sides on, it will extrude 1mm in both directions resulting in 2mm from its center.
Step 7: Copying Shapes in a Polar Array
Now we want to create multiples of the form revolving around a center point.
This command is called Polar array. Type "ArrayPolar" + enter or click and hold the array icon and unclick with the Polar array icon.
In the right view port, click the solid. Type "0" +enter for the center point. And "5" + enter for five copies of the solid (or however many you want)
Value = "360" + enter (This will make a full circle polar array)
Step 8: The Twist
Now we want to twist the object.
1. Select all the solids by holding shift and clicking or by typing "SelPolysrf" + enter
2. Type "twist" or in the dropdown menu transform / twist
3. In the top viewport, click from "0" to the end of the shape. In the right viewport you will begin the start angle. click and type a value = "360" + enter
Step 9: Mirror
Now we will create the other side of the Vajra.
1. Select all the solids and type "mirror" + enter or in the dropdown menu transform / mirror
2. In top view, type "0" + enter for the center point and click 90° for a mirrored form.
Step 10: Boolean Union
*This step may be optional. Sometime there are issues with the shells and parts need to be connected as one solid piece. But this is advanced 3D printing terminology.
1. Type "BooleanUnion" +enter or select the boolean union icon and start selecting solids.
Boolean union is an advanced command and could have a few failed unions.
Step 11: Export and Upload
1. Export as an .STL and upload to Shapeways
Unfortunately this form may be hard to produce on a desktop printer but its worth a shot.