I haven't really seen this in real life, but I have seen it in some of the games I play. A vaulted ceiling that is a pillarless pillar .... kinda thingy.
It's hard to explain so here's some ingame pictures to give a better idea.
With a diamond shaped finish as the bottom detailing.

An ingame shot with the original mesh texture by Mio.
With a pearl/ball shaped finish as the bottom detailing.

An ingame shot with the original mesh texture by Mio.
The new meshes are based off that magnificent treasure created by Mio0331,
his/her Gothic Arch Pillars at MTS. I remapped the three pillars in the set in order to make recolouring easier. All recolours are based on the central column A. I had made some recolours earlier that you can find
here. As in the original creation, there are 3 columns -- column A, the centre column; column B, the sidewall column and column C, the corner column. The new meshes follow along the same line. The new mesh is also double faceted so when you use the design tool you can see the recolour texture much easier. It will impede your view into the room from a bird's eye view (the top looking down button)however. And remember that the footprint of the "column" will still be on the floor so Sims may walk around the invisible column.