The ventricles in this full-sized anatomically correct human heart are large enough to hold a nice selection of chocolates. For your weirdo Valentine. Or cardiologist. The model can be used again for Halloween.

See here for video: https://youtu.be/k8YbW3daSc0

There are four versions provided: “Plain,” “Magnet,” “Supports,” and “Support Magnet”. Each version includes a “Lid” and “Base”

In the “Plain” version, the Lid is held loosely in place with the overlap of the atria around the ventricles. If you want the lid held more securely, print one of the “Magnet” versions and insert four 3mmx3mm (1/8” x 1/8”) cylindrical neodymium magnets into the two holes in the Lid and Base.

The “Supports” versions are pre-supported on the inner overhangs that are not reachable from the build plate. You will still need to add supports to the bottom.

Print both files as oriented. The “Base” prints in normal orientation, but the lid needs to print upside down to preserve the smoothness of the contact area and ensure that the lid fits nicely on the base.

I recommend raising the Lid off the surface of the build plate by 3mm and building tree supports underneath. This means that you will need to do a bit of cleanup on what will become top of the lid.