Yin-Yang Helicoidal Sphere

This project is a three-dimensional interpretation of the Yin-Yang symbol, designed as a partially spherical object with a helicoidal geometry.

The model is composed of four separate parts:

• Two large helicoidal spherical shells, complementary and interlocking
• Two helicoidal locking elements, acting as pseudo-axes

The assembly principle is intentionally simple and purely mechanical:
the two main spherical parts are first brought together and aligned, then locked into position by inserting the helicoidal elements, with no screws, no glue, and no supports.

This project allowed me to explore:

• the design of complex and continuous geometries,
• helicoidal interlocking mechanisms within a spherical volume,
• and the limits of support-free FDM 3D printing, both in terms of geometry and assembly precision.

3D Printing

• No AMS is required: all parts can be printed in a single color and assembled afterward.
• The model can be printed on any well-tuned FDM 3D printer.
• Special attention must be paid to build plate cleanliness to ensure proper first-layer adhesion.
• Do not increase the first-layer printing speed in your slicing profiles, as this is critical for adhesion and dimensional accuracy on the helicoidal surfaces.

This is a small object, but a true advanced design exercise, at the intersection of symbolic design and mechanical 3D printing.