Print-in-Place: 20 Models That Print Fully Assembled

Print-in-place models are the magic trick of 3D printing. You start a print, walk away, and come back to a fully assembled object with moving parts — hinges that swing, gears that turn, joints that flex. No glue, no screws, no assembly instructions. Everything is built in one continuous print.

The secret is clever engineering. Designers create tiny gaps between interlocking parts that are small enough to keep the parts captive but large enough that they do not fuse during printing. It is a delicate balance that pushes both the design and the printer to their limits.

Here are 20 of the best print-in-place models across a range of categories. Each links to 3DSearch for finding the best version.

Fidget Toys and Desk Toys

1. Fidget cube — A multi-sided cube with buttons, switches, spinners, and sliders on each face. Prints as one piece with all mechanisms functional. Perfect desk toy. Search for fidget cubes on 3DSearch

2. Gear bearing — A planetary gear set enclosed in a ring. Spin the center and the planets orbit smoothly. Hypnotic to play with and great for demonstrating gear mechanics. Search on 3DSearch

3. Infinity cube — A chain of eight cubes connected by hinges that fold endlessly in any direction. One of the most satisfying fidget toys and a show-stopper when printed cleanly. Search on 3DSearch

4. Gravity knife toy — A retractable blade toy (non-sharp) that flips open and closed with a satisfying click. Not a real knife — just a fidget mechanism. Hugely popular on TikTok and YouTube. Search on 3DSearch

5. Articulated slug — The viral print-in-place slug with segmented body and googly eyes. Simple to print, impossible to stop fidgeting with. Search on 3DSearch

Functional Print-in-Place

6. Print-in-place pliers — Working pliers that print flat and fold into a functional tool. They actually grip things. Not strong enough for serious work, but proof of what print-in-place can do. Search on 3DSearch

7. Folding phone stand — A stand that prints flat and folds into position with built-in hinges. Compact enough to carry in a bag and sturdy enough to hold a phone. Search on 3DSearch

8. Print-in-place box with lid — A box with a hinged lid that prints as one piece. The hinge is the print-in-place element. Some designs include a snap-close latch. Great for storing small items. Search on 3DSearch

9. Flexible wrench — An adjustable wrench with a sliding jaw that prints fully assembled. The worm gear mechanism actually works to adjust the jaw width. Search on 3DSearch

10. Collapsible sword — A telescoping sword that extends with a flick of the wrist. Multiple nested segments slide out and lock into place. Enormous fun for kids and adults. Search on 3DSearch

Animals and Creatures

11. Articulated dragon — The crown jewel of print-in-place. Dozens of interlocking segments create a fully poseable dragon. Silk filament makes these look extraordinary. Search on 3DSearch

12. Flexi Rex — The original articulated dinosaur. A T-Rex that prints flat with linked segments that flex into a standing pose. If you have never printed an articulated model, start here. Search on 3DSearch

13. Articulated octopus — Eight independently poseable tentacles attached to a body. Prints upside-down and flexes loose beautifully. Search on 3DSearch

14. Articulated turtle — A turtle with a moving head, legs, and tail that retracts into the shell. Charming design that kids love. Search on 3DSearch

15. Articulated caterpillar — A friendly multi-segment caterpillar that wiggles and poses. Easy to print and a great beginner articulated model. Search on 3DSearch

Mechanical Marvels

16. Working clock mechanism — A functioning gear train with escapement that you can turn by hand to see how a clock works. Does not keep time, but demonstrates the mechanism beautifully. Search on 3DSearch

17. Planetary gear set — A complete planetary gear system that prints as one piece. Spin the input and watch the output turn at a different speed. Educational and mesmerizing. Search on 3DSearch

18. Geneva mechanism — A classic intermittent motion mechanism used in watchmaking. Continuous rotation on one side produces stepped rotation on the other. Prints in place with smooth action. Search on 3DSearch

19. Ball maze — A maze with a captive ball inside that you tilt and twist to navigate the ball through channels and past obstacles. The ball is printed inside and cannot be removed. Search on 3DSearch

20. Cryptex — A combination lock cylinder inspired by The Da Vinci Code. Rotating rings must be aligned to the correct letters to open the cylinder and reveal a hidden compartment. Prints fully assembled with all rotating parts. Search on 3DSearch

How to Succeed with Print-in-Place Models

Print-in-place models are more demanding than standard prints. Here is how to get them right:

Critical Settings

• Elephant foot compensation: This is the single most important setting. Enable it in your slicer (usually 0.1-0.2 mm). Without it, the first layer spreads wider than intended and fuses moving parts together.
• Flow rate: Calibrate your flow rate precisely. Even 5% over-extrusion can fuse joints. Run a flow calibration cube and measure the walls with calipers.
• First layer height: Use your normal first layer height (usually 0.2-0.3 mm) but make sure the Z offset is not too low. A squished first layer is the enemy of print-in-place.
• Cooling: Maximum fan speed from layer 2 onward. Good cooling prevents material from drooping into the gaps between parts.
• Speed: Moderate speed (40-60 mm/s for walls). Ringing and vibration at high speeds can fill in the tiny gaps that keep parts separate.

Best Material

PLA is the gold standard for print-in-place models. It bridges well, cools quickly, and prints with clean edges. Avoid PETG for print-in-place — its stringing tendency fills gaps between parts.

• Hatchbox PLA — Consistent diameter and quality
• TTYT3D Silk PLA — Stunning finish for display pieces
• eSUN PLA+ — Slightly tougher joints that resist breaking
• Overture Matte PLA — Hides layer lines for a premium feel

Freeing Stuck Parts

Even with perfect settings, print-in-place parts often need a little help to move freely:

1. Gently flex each joint back and forth. Apply steady pressure — do not yank.
2. For gears and rotating parts, try turning them slowly in both directions while applying light axial pressure.
3. If a part is truly fused, use a thin blade (X-Acto knife) to score along the seam line.
4. Brief immersion in warm water (not hot) can soften PLA enough to free stubborn joints.

Test Prints

Before committing to a multi-hour print-in-place model, print a small test piece first. Many designers include a tolerance test file alongside their main model. Print it, check if the joints move freely, and adjust your settings before printing the full model.

The Art and Engineering of Print-in-Place

What makes print-in-place fascinating is the intersection of mechanical engineering and additive manufacturing. These designs exploit the unique capabilities of layer-by-layer printing to create assembled mechanisms that would be impossible to produce any other way.

Designers in this space are pushing boundaries constantly. Communities on Reddit's r/3Dprinting and r/functionalprint showcase new print-in-place designs regularly. Platforms like Printables and MakerWorld have dedicated categories for these models.

Use 3DSearch to find print-in-place models across all platforms. Search for "print in place" plus whatever you are interested in — toys, tools, mechanisms — and see every available design in one place.

What print-in-place model will you try first?