this is a prototype mag stand to hold a piece of sculpture or any other small magnetic object.
The column up the middle is just support material. it should snap at the thin seem revealing the cavity that will receive a 8mmx3mm disk magnet. Edit: I have also added a version with the support structure removed for those who require this.
Disclaimer: The opening for the magnet is very slightly oversized, but depending on your printer, this opening may be too large or too small. The 8mm magnets I have found are not great on tolerance either so some variability here is going to come into play.
I had to open up the hole in my stand slightly with a drill bit, sand paper would have worked as well. You may find you have the opposite issue of the magnet being too loose. A little glue can be of help in that situation.
My point is, I have done my best to make this a good size but some fiddling may be required due to things outside of my control.