This was a fun project. This is a six sided dice that has a interior structure so that when its rolled the weight always ends up on one of the numbers displaying the corresponding number.

I'm including the interior geometry because I thought is was an interesting shape. 

I used the Prusa slicer cut and connector feature to add 3 dowels. In reality I need to scale down the dowels after I performed the cut. I used a 45 degree y axis + a 45 degree x axis to split the model without cutting any of the numbers. 

The original model is 100x100x100 but should scale down with little issue to the size of the weight you are using. But you need to Split it yourself.

I also used a very fine layer height with adaptive - smooth layers, but still required a bit of sanding to be smooth.