Rock with secret compartment - for geocaching

One of the things our family loves is taking hikes. We did a few Geocache walks, which were really fun.

Geocaching is an outdoor treasure-hunting activity using GPS coördinates to find a hidden container (called geocaches or caches). They are most of the time well hidden or, camouflaged as an item that belongs in the environment.

So, if you want to create your own Geocache, treasure hunt or simply want to hide something clever, you can use this rock model with a secret compartment.

The compartment is a bit less then 5 cm (2 inches) high, so if you would want to hide a key, print the model at 150%. Then the opening is about 7,5 cm x 6 cm (3 inches x 2,3 inches).

The print is supportless. It is necessary to print the rock at a high quality setting, because otherwise you will have to big layerlines that even a good paint job will not cover enough to make the rock look realistic. And high quality takes time to print 😊

Edit 20th of April 2025: changed the design of the cap so it is round at the bottom and it doesn't have any overhang - this should solve the issue some people were having.

Edit 21th of April 2025: added a profile specificly for 50% size, because the cap was not designed to be printed this small. The specifily designed cap has extra strenght on the sides, making it possible to print at 50%, but this means that the compartment is smaller then in the original design. At 50% with the special cap you have a compartment of 2cm x 1,5 cm.

Painting advise: print in Grey (matt) (depending on what shade the other rocks are), prime, drybrush with grey and white, add matt varnish and hide away!

Be aware PLA melts, so hide it in a shady spot when using PLA.

By request I tried making my very first painting tutorial to help you with the process of making your rock look more realistic.

This video was made with one of my earlyer prototypes when perfecting the model, so it is smaller then the final model that was uploaded.