Many of you are already familiar with the image of a goblet that looks like a person's face. I found Instructables on how to "Make a Vase with the 123D..." and "3D Printed Face Goblet," but as I tried to explain them to my kids, it was apparent that we all got a bit lost in the software to appreciate what was going on.
To better explain the underlying 3D principles of profiles, rotations and layers, I came up with the following activity that uses Word and Excel to create an electronic "face." As a TechShop member I have access to a laser cutter, so I also created a set of rings that could be stacked to create a physical model.
Step 1: Materials
1. A side view image of a person's head
2. Microsoft Word (or any graphics program)
3. Microsoft Excel (or other charting software)
6. Cardboard, approximately 1/16" (1.5mm) thick
7. Marker, about as wide as the cardboard
8. Laser Cutter (Optional - for making a physical model)
Step 2: Estimate the Size of Your Vase
More layers will give you better resolution, but that means more pieces to cut. Start by estimating the thickness of 50 layers of cardboard. In this example my cardboard is approximately 1/16" (1.5mm), so my vase will be about 3" (8cm) high.
Note: This doesn't have to be exact as layer thickness and the number of layers is part of the exercise.
Step 3: Import Photo and Print Vase Profile
1. Import photo into Word (Image from secondpicture.com)
2. Adjust the size so that the vase is about the size that you had calculated (again, not critical).
3. Make a copy and mirror the images so that they are facing each other.
Tip: Don't get the faces too close together, otherwise the profile can get too narrow if you plan to build a physical model.
4. Print it out and trace the outline of your vase.
Step 4: Take Measurments
1. Measure the top of the vase and record the length.
Tip: Recording lengths in mm is faster and will make data entry into Excel easier.
2. Move ruler down the width of your pen, draw another line, and record the length.
3. Continue until you reach the bottom. You'll see the vase appear as you fill it in line by line.
Step 5: Enter Length Data Into Excel
1. After entering the data into Excel, highlight it and select "INSERT" and then "COLUMN CHART." Other chart types will also work, but the column simulates a stacked layer model.
2. A sideways "face" should appear. If the face does not look correct, double check your data for errors.
3. At this point you can fine tune the data (my chart definitely needs adjustment) or try different values: a) Try to create Pinocchio's nose, b) Delete every other row to see how it affects the resolution, or c) Add rows to create a stretched face.
Step 6: Laser Cut Circles (Optional)
If you have access to a laser cutter you can quickly make all the circles that you'll need (plus extras in case you lose some or want to make different faces). Include a small center hole for inserting a string or a larger one for stacking over a pencil.
Tip: Take the time to laser etch the size onto each circle to make sorting easier.
Step 7: Start Stacking
You can take a peek when you reach the halfway point. Use a contrasting background to see the outline better.
Step 8: Completed Models
Gift Ideas: Send someone a unique puzzle (bag of disks and a stacking order), or just email them your Excel data and have them graph it.
While scanners will help eliminate the need to learn multiple software packages, the underlying principles remain the same. Hopefully this manual exercise gave my kids a better understanding of what is happening when software is used to select a profile, rotate it, and to 3D print (or laser cut in this case) a face vase.
Step 9: Circle Templates
It took quite a bit of time to lay out the circles and label them, so I have attached templates in CorelDraw and Adobe Illustrator for circles 1.0-7.0cm in diameter with a center hole that is loose over a straw or tight over a #2 pencil.