I know how to do that in UE Editor so I thought it could be done in CORE. Basically if the brush/cube has the anchor gizmo at the center of the piece, you're able to snap it to a corner so that when you scale it or rotate it, it scales and pivots from that corner, for easier arrangement of the piece. I found out that some asset walls already has the pivot on a corner so rescaling them is very easy, whereas by having the pivot on the center it resizes the piece in all 4 directions and you need to drag it around every time to align it better with the rest of the environment (specially if you are doing building interiors).
I use the default cube as I use the brush in UE Editor, to create the draft of the level map. Snapping the gizmo to a corner of the asset would speed up our workflow several miles. Thanks for reading.