Master the duplicate feature to create multiple components. Design a pop-it style fidget toy with custom-sized holes. Learn to use the hole feature and combine shapes effectively.
Open TinkerCAD with a new blank design and get familiar with the default workplane grid.
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Parent note: If you completed Episode 1, you already have a TinkerCAD account. Just log in and click "Create" → "3D Design" to start a new project.
Get started
1Log in to tinkercad.com (or create a free account if this is your first time).
2Click "Create" then "3D Design". A new empty workplane opens.
3Notice the blue grid on the workplane, the default grid size is 20mm.
4Rename your project by clicking "Untitled" at the top left, call it "My Pop-It Fidget".
5Take a moment to orbit the view (right-click drag) and zoom (scroll wheel) to get comfortable.
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You can change the grid size by clicking the "Edit Grid" button at the bottom right of the workplane. The default 20mm grid works great for this project.
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Knowledge Check
+15 XP
What is the default grid size in TinkerCAD?
A10mm
B20mm
C50mm
2
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Create the Base Plate
Build a rounded rectangle 80mm x 60mm x 4mm
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Goal for this step
Create a flat rounded rectangle that will be the base of your pop-it fidget toy.
Build the base
1In the Shapes Panel on the right, find "Box" under Basic Shapes (we'll round it).
2Actually, look for "Round Roof" or use a "Box", drag it onto the workplane.
3Click the shape to select it. Set the width to 80mm, the depth to 60mm, and the height to 4mm.
4Use the dimension boxes that appear when you click the white handles to type exact values.
5You should now have a flat, rectangular base plate sitting on the workplane.
What you should see: a wide, flat slab, like a chocolate bar lying on the grid. Type the numbers into the dimension boxes: 80 wide, 60 deep, 4 tall. If yours looks like a tall tower, the 4 went into the wrong box.
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A 4mm thick base gives enough material for the bubbles to push into while staying thin enough to feel satisfying when popped.
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True or False?
+15 XP
A thicker base makes the pop-it harder to pop.
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Knowledge Check
+15 XP
What are the dimensions of the base plate?
A60mm x 40mm x 8mm
B100mm x 80mm x 4mm
C80mm x 60mm x 4mm
3
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Create One Bubble
Use a half-sphere, 10mm diameter, for the first bubble
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Goal for this step
Create a single bubble shape using a sphere, sized to 10mm diameter.
Make the first bubble
1In the Shapes Panel, find the "Sphere" under Basic Shapes.
2Drag the sphere onto the workplane, placing it near (but not on) the base plate.
3Resize the sphere to 10mm x 10mm x 10mm, this gives a 10mm diameter bubble.
4We only need the top half, we'll position it so the bottom half sinks into the base plate later.
5This single bubble is the template we'll duplicate to create the full grid.
Drop the sphere on empty grid, not on the plate. We will line everything up properly with the Align tool in step 7, so a rough position is fine here.
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The sphere creates a nice rounded bubble shape, just like on a real pop-it toy!
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Knowledge Check
+15 XP
Which shape do you use for a bubble?
ACylinder
BBox
CSphere
4
📋
Duplicate a Row of 4 Bubbles
Learn Ctrl+D to duplicate, space bubbles 15mm apart
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Goal for this step
Use the Duplicate feature to create a row of 4 bubbles, each spaced 15mm apart.
Duplicate your bubble
1Select your bubble sphere. Press Ctrl+D to duplicate it.
2A copy appears on top of the original. Don't click away! Move it 15mm to the right using the arrow keys or by dragging.
3Press Ctrl+D again, TinkerCAD remembers the 15mm move and creates another copy spaced perfectly!
4Press Ctrl+D one more time for the 4th bubble. You now have a row of 4 bubbles spaced 15mm apart.
5Check that all 4 bubbles are in a straight line and evenly spaced.
15 mm centre to centre leaves a 5 mm gap between the 10 mm bubbles. Bubble ① is your original; each Ctrl+D repeats the copy AND the 15 mm move, so ②, ③ and ④ land perfectly spaced.
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The Ctrl+D repeat trick remembers your last move, this is how pros create evenly spaced patterns quickly!
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Fill in the Blanks
+15 XP
Press to duplicate. Space each bubble apart.
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Knowledge Check
+15 XP
What keyboard shortcut duplicates a shape in TinkerCAD?
ACtrl+D
BCtrl+C
CCtrl+G
5
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Create a 4x3 Grid of Bubbles
Duplicate the row to make 12 bubbles total
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Goal for this step
Duplicate the row of 4 bubbles to create a 4x3 grid, 12 bubbles total.
Build the grid
1Select all 4 bubbles in the row, click and drag a selection box around them, or hold Shift and click each one.
2Press Ctrl+D to duplicate the entire row.
3Move the duplicated row 15mm forward (toward you) to create the second row.
4Press Ctrl+D again, TinkerCAD repeats the duplication and the 15mm forward move automatically!
5You now have a 4x3 grid of 12 bubbles, all evenly spaced. Count them to verify!
Select the whole row first (drag a box around all 4), then Ctrl+D and move the copy toward you. TinkerCad treats the row as one thing, so the spacing inside the row stays perfect.
✅Checkpoint: count your bubbles, there should be exactly 12, in 3 neat rows of 4. A wonky bubble means a drag slipped; click it and nudge it with the arrow keys (each press moves 1 mm).
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4 columns times 3 rows = 12 bubbles. The Ctrl+D repeat trick works with multiple selected shapes too!
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Knowledge Check
+15 XP
How many bubbles are in a 4x3 grid?
A7
B12
C16
6
🕳️
Change Bubbles to Holes
Select all bubbles and set them as "Hole" in the inspector
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Goal for this step
Convert all 12 bubble spheres into holes so they'll punch through the base plate when grouped.
Make the holes
1Select all 12 bubble spheres, drag a selection box around all of them, or use Ctrl+A then Shift-click the base plate to deselect it.
2With all bubbles selected, look at the shape properties in the top-right corner of the screen.
3Click "Hole", all the spheres turn translucent with a striped pattern.
4This means they are now holes, when grouped with the base plate, they will subtract material.
5The bubble shapes are still there, but they'll cut into the base plate to create the pop-it dimples.
All 12 at once: drag one big selection box around just the bubbles, then click "Hole". Every sphere should turn grey and stripey. If the base plate turned stripey too, it got caught in your selection, undo and try again.
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The Hole feature in TinkerCAD works like a cookie cutter, it removes material from solid shapes when they are grouped together.
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True or False?
+15 XP
Holes subtract material when grouped with solid shapes.
Hole shapes appear translucent with stripes in TinkerCAD.
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Knowledge Check
+15 XP
What happens to holes when you group them with solid shapes?
AThey subtract material from the solid shapes
BThey become solid
CThey disappear completely
7
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Align Bubbles on the Base Plate
Center the bubble holes on top of the base using Align
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Goal for this step
Position the bubble grid centered on the base plate using the Align tool.
Center the bubbles
1Select all 12 bubble spheres first (drag a selection box around them).
2Now hold Shift and click the base plate to add it to the selection.
3Click the "Align" tool in the top toolbar (or press the L key).
4Black alignment dots appear. Click the center dot on the X-axis (left-right) to center horizontally.
5Click the center dot on the Y-axis (front-back) to center vertically.
6The bubble grid should now be perfectly centered on the base plate!
The Align tool shows little black dots along each edge and centre. Click the centre dot on each axis (shown purple above) and the bubble grid snaps to the exact middle of the plate.
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The Align tool is essential for precision. It removes the guesswork of centering objects manually.
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Put It In Order
+15 XP
Put these in the correct order to align bubbles on the base:
Click Align (or press L)
Select all bubbles
Center vertically (Y-axis)
Shift-click the base plate to add it
Center horizontally (X-axis)
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Knowledge Check
+15 XP
What keyboard shortcut opens the Align tool?
AA
BL
CG
8
🔗
Group Everything Together
Group so holes punch through the base plate
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Goal for this step
Group the base plate and all bubble holes together so the holes punch into the base.
Group and verify
1Press Ctrl+A to select everything on the workplane, the base plate and all 12 bubble holes.
2Press Ctrl+G to group them all together.
3The holes cut into the base plate, leaving 12 round dimples, your pop-it bubbles!
4Orbit the view to check your design, you should see neat, rounded indentations in the base.
5If something looks wrong, press Ctrl+Z to undo, fix the issue, then group again.
What you should see: one solid plate with 12 smooth, rounded dents, like an egg box. Orbit the view: the dimples should dip INTO the plate, not poke out of it.
✅Checkpoint: if the bubbles vanished completely and left no dents, they probably were not touching the plate, undo the group, and lower the spheres so they sink halfway into the plate before grouping again.
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After grouping, rotate the view to see the bottom, the holes should go partway through the base, not all the way.
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Knowledge Check
+15 XP
What keyboard shortcut groups shapes together?
ACtrl+D
BCtrl+A
CCtrl+G
9
🔲
Add a Border Rim
Duplicate the base, scale up, and create a raised border
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Goal for this step
Create a raised border rim around the pop-it by duplicating the base and using the hole technique.
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Parent note: This step uses a clever trick, we duplicate the base, make it slightly bigger, then use the original size as a hole to create a hollow rim. This is a powerful 3D modeling technique!
Create the rim
1First, Ctrl+Z to ungroup if needed, or start fresh: create a new box the same size as your base (80mm x 60mm x 4mm).
2Duplicate the base plate shape with Ctrl+D.
3Scale up the duplicate, make it 5mm larger on each side (so 90mm x 70mm x 6mm for the outer rim).
4Make the original-sized shape a Hole.
5Align both shapes centered, then Group them, the inner hole cuts away, leaving just a border rim!
6Position this rim around your pop-it base and group everything together.
Box minus box = frame. The big solid box, with a plate-sized Hole aligned in its middle, groups into a picture-frame rim that slots around your pop-it.
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This "duplicate, scale, subtract" technique is used by professional 3D modelers all the time to create hollow shapes and borders.
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Fill in the Blanks
+15 XP
Duplicate the base, scale it each side, then make the original a .
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Knowledge Check
+15 XP
What technique do we use to create a hollow border rim?
ADuplicate, scale up, make original a Hole, then Group
BDraw a rectangle border by hand
CUse the Border tool from the menu
10
✏️
Add Your Name with Text
Use the Text shape to personalize your pop-it and customize colors
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Goal for this step
Add a personalized text shape with your name and choose fun colors for your pop-it.
Personalize your design
1In the Shapes Panel on the right, look under "Basic Shapes", find the "Text" shape.
2Drag the Text shape onto the workplane near your pop-it.
3Click on it and in the Shape Properties panel, type your name or a short word.
4Resize the text to fit nicely on the border rim of your pop-it. Make it about 2mm tall so it's raised but subtle.
5Position the text on the rim and group it with the pop-it.
6Now select your whole design and choose a fun color from the color picker in the Shape Properties!
Keep the letters low (2 mm) so they print cleanly and do not get in the way of popping. Drag the Text shape onto the rim, type your name in Shape Properties, then shrink it to fit the rim band.
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Try bright colors like purple, teal, or pink, they'll look great when 3D printed!
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Knowledge Check
+15 XP
Where do you find the Text shape in TinkerCAD?
AIn the Edit menu
BIn the Basic Shapes panel
CIn the Settings menu
11
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Export as STL & Learn About TPU
Download your design and learn about flexible filament for pop-its
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Goal for this step
Export your pop-it as an STL file and learn why TPU filament is the best choice for flexible pop-its.
Export and filament choice
1Click the "Export" button in the top-right corner of TinkerCAD.
2Choose "STL" as the format and download your file.
3For a pop-it, filament choice matters! PLA is rigid, it works but won't be flexible.
4TPU (Thermoplastic Polyurethane) is a flexible filament, perfect for pop-its that actually pop!
5TPU prints at slightly lower speed and higher temperature than PLA. Ask your printing service about TPU options.
6Recommended slicer settings for TPU: Layer height 0.2mm, Infill 15-20%, Print speed 25mm/s (slower than PLA).
Export → .STL, then ask for TPU filament when printing. TPU is bendy, so the bubbles actually pop back and forth; rigid PLA works but the bubbles stay stiff.
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Parent note: TPU can be trickier to print than PLA, it requires a direct-drive extruder for best results. If your printer only has a Bowden tube, PLA with thin walls can still create a semi-flexible pop-it.
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True or False?
+15 XP
PLA is the best filament for flexible pop-its.
TPU stands for Thermoplastic Polyurethane.
TPU prints at a slower speed than PLA.
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Final Knowledge Check
+15 XP
Which filament is best for flexible pop-its?
APLA
BTPU
CABS
🛠️ Printed it and something's not right?
The bubbles don't pop, the whole thing is stiff. It was printed in PLA, which is rigid. Pop-its need the flexible filament TPU (step 11). A PLA pop-it still looks great, it just works as a fidget dish rather than a popper.
There are no dimples in the top, it printed as a flat slab. The spheres were not set to Hole, or they were floating above the plate when you grouped. Each sphere must be sunk into the plate so they actually cut into it.
A wall between two bubbles cracked. Those bubbles were closer than the 15mm spacing, leaving a paper-thin wall. Nudge them apart in TinkerCad and re-export.
The plate corners lift and warp during printing. Large flat prints like this need good bed adhesion. Ask for a brim, and if printing in TPU, a slower first layer.
🎉🫧🖨️🎊🔧
You Designed a Pop-It Fidget!
Amazing, you've mastered duplicating, holes, alignment, and the border rim technique. Now try Episode 3!
