It's not

Unfortunately not. At least I haven't found a way.

Allright, thanks for the reply!

While it’s not always necessarily easy, if you’re placing things like smoke or fire jets, if you move them around over other scenery objects, they’ll move onto their sides/angles.

There's an experimental and unpublished mod available on the Discord (not on the workshop) that allows free rotation in any direction you like, it's called Freedom2000. Join and ask on discord if you can't find the download link.