Lung Air Sacs

Air sacs model, divided into two pieces

Description of the model

The air sacs are part of the respiratory system at the end of the bronchioles (tiny branches of air tubes in the lungs). The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out. Oxygen breathed in from the air passes through the alveoli and into the blood and travels to the tissues throughout the body. Carbon dioxide travels in the blood from the body’s tissues and passes through the alveoli to be breathed out.

This model is hollow and divided into two sections to show the organ from the inside and outside.

There is an alternative model which prints in one piece to only show the outside of the structure. It is technically easier to print.

Air sacs printed and divided into two partsAir sacs printed an merged together

Alveolus_H_P1 and Alveolus_H_P2 contain a version with holes for magnets of 1mm in height and 3mm in diameter in case you prefer to use magnets instead of glue.

This model was designed and tested as part of the 3D4VIP project.

Printing instructions and tips

There are two alternative options to print.

If you want to print the full model with access to the interior of the structure use the models Alveolus_p1-1.stl and Alveolus_p2-1.stl. In this case, please consider using support structures. Use of 1mm magnets to hold the two parts together is recommended.

As an alternative, if you don’t need to access the interior structure, use the Alveolus-2.stl model. Although it should not require support, if you want to print it with SLA printers, we recommend adding some support to ensure it sticks to the base plate.



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  • Rotate with the left mouse button.
  • Zoom with the scroll button.
  • Adjust camera position with the right mouse button.
  • Double-click to enter the fullscreen mode.
  • On mobile devices swipe to rotate.
  • On mobile devices pinch two fingers together or apart to adjust zoom.
  • On mobile devices 3 finger horizontal swipe performs panning.

Additional Models

  • Alveolus_p1-1.stl
  • Alveolus_p2-1.stl
  • Alveolus_H_P1_Alt-1.stl
  • Alveolus_H_P2.stl