Okay, I haven't created an objectified walking staircase but I did modify the bases for two different staircases back in the day. One sims can walk beneath and the other they can place objects beneath. Okay, technically you can place objects beneath both of them but it wouldn't make sense to walk under a staircase that is surrounded by a cage, would it? So here they are.
Since it was requested recently, I figured it would be good to repost for everybody.
There were no updates on these because the originals were perfect, right?