Windows made to be compatible with Duplo bricks.

Snug fit on top and bottom to ensure a secure fit.

If you make one, please share it in the comments — I’d love to see it!
And if you run into any issues, please let me know so I can improve it further.

Print profile plates

• All on separate plates: Use this profile if you have an A1 Mini or prefer to print the parts individually.
• Print by object: Use this profile to print the window and opening together, optimized for minimal material waste.

Assembly

Please be careful when assembling the window — incorrect assembly can cause damage.
You can see a small “scar” on the first image as an example of what can happen.

To avoid this, please follow the assembly guide carefully.

1. Find the dimple in the opening and bulge in the window.

   

2. Press the bottom window bulge into the dimple in the opening.

3. Push the upper part into the upper dimple in the opening from the side.

   

   

4. The window should now work as expected.

   

    

Changelog:

11.09.2025: @JJ.Grasnarbe pointed out some strength issues and provided excellent suggestions for improvements. Based on that feedback, I’ve made several changes:

• There are now three types of windows: Original, Reinforced, and 6-Stud.
• All windows are printed at a 45° angle with supports, which improves strength, surface quality, and dimensional accuracy.
• The dimple design in the windows has been updated — it’s now 0.4 mm longer to maintain the same locking feel as before.
• Print profiles have been updated:
  • One profile for all parts on different plates.
  • One profile using “print by object”, optimized for printing the window and opening with minimal material waste across different printers.

12.09.2025: 

• Minor changes to support, to ensure best surface quality. 
• Rounded the “holders” that stick to the bricks, so its easier to use, without loosing grip.
• Removed unnecessary brim.