The process of creating 3D reconstructions of human embryos which form the basis of the 3D prints is both meticulous and innovative, grounded in historical and modern techniques. The embryos used in our educational 3D prints are primarily sourced from historical specimens collected between 1910 and 1975. These specimens were gathered from ectopic pregnancies, hysterectomies, and miscarriages, with many coming from the renowned Carnegie collection in Washington, D.C.

To create these detailed 3D models, the process begins with histological sections of the embryos. These sections are digitized using a digital microscope. Each image is meticulously aligned to ensure accuracy. (Bio)medical students under supervision of experienced embryologists then segment the various embryonic structures by hand, using Amira software to outline each organ and tissue in the grayscale images, often referring to color images displayed on a secondary screen.

Once the segmentation is complete, the data is further processed to create a three-dimensional surface model. This model undergoes several steps of knowledge-driven modelling, including smoothing and reduction of complexity, to make it suitable for educational use. Specialized 3D modeling software Blender is used to correct any artifacts and ensure the model’s anatomical accuracy.

The final models are exported and converted into interactive 3D-PDFs, allowing users to explore the intricate details of embryonic development from different angles and levels of zoom. These digital models serve as invaluable tools for teaching and research, providing a clear and accurate representation of human embryonic development that is accessible to educators, students, and medical professionals alike.

The 3D Embryo Atlas is a freely available digital resource which was published in Science in 2016. Since then, the digital models have been used in biomedical curricula worldwide, with hundreds of thousands of downloads per year.

The 3D Embryo Prints are based on the famous 3D Embryo Atlas; the models and color use are alike to facilitate simultaneous use of both the 3D prints and the free online models in embryological education.