This model is part of a set of three sizes of spiky sea urchin shells. Careful, they’re sharp!
See here for video: https://youtu.be/2FuPJwsSXlM
See here to download the set: https://than.gs/m/932681
These high-resolution models are designed for resin printing. Walls are 1mm thick, so the prints require minimal material and can be translucent depending on the type of resin used.
Other Sea Urchin Designs:
Bumpy: https://than.gs/m/929027