Giving the columns a way to integrate in the walls

columns are now free standing objects. it would be nice if we could make them integral part of walls as well.. so as to, for instance, be the support for 2 adiacent arches, or just a decorative feature of a wall rather than a support for an invisible ceiling.
to do this, the columns should have a toggle that makes them incorporeal so that we can superimpose them on walls or other features. (toggle because we still need them to function in their current status)…

by the way, in their current status, it would be nice if we could place some light fixtures on them, like torches and such.