Sand Spheres

The spheres pictured were printed with 60% in-fill at their 50-mm/2-inch size - enough weight to push into the sand as you roll the sphere across. The layer height wasn't noticeable on the sand - it is not high resolution. My prototypes having slight support scarring on the bottom wasn't an issue. The fine sand was $5 at local craft stores, enough for a 10-inch diameter circle of sand, about 3/4-inch deep.

I considered making silicone molds and pouring concrete into the molds, but in the end that was a lot of work for a one-off sand art experiment.

Notes:

The voronoi sphere turned out much better the second time when I generated tree supports for it (used MeshMixer).

They're all manifold objects in Blender, but the "large bubble" sphere still had some weird overlap issues at a couple of intersections - not noticeable in the sand, but visible on the printed object.

How I Designed This

They were all designed in Blender - some were trivially easy, some were generated by some new-to-me processes, and some were just painful amounts of copy-paste sizing (the bubble spheres, miserable).

Each one had its own process (except for TinyBubble and LargeBubble, which were the same tedious process). Feel free to message me, if you want to discuss how an individual one was designed.

If you're going to try your own, I would recommend trying something with an easy repeating pattern. Sharp edges work much better than smoothed/beveled edges. I used a cube with subdivision surface modifier for a more even size of each face - the standard spheres will give you headaches otherwise.

My favorite one to design and roll was probably the voronoi one - based on the method from Luxxeon 3D's youtube video "Blender 2.8 Tutorial | Parametric Voronoi Sphere | 3d Modeling".