This dice is a ball outside and has a hollow octaeder inside. In the octaeder cave there is a steel ball, that you have to fit before glueing the half shells.

The size is designed for a 8 mm steel ball, scale to another ball size if necessary.

How to use: Throw it like a normal dice, it will always stop with points (1 to 6) up, despite being a ball shape outside.

For those, who don't want to glue two half shells but instead want to interrupt the print for insertion of the steel ball, I've added an stl with the dice as a whole.