Tube command doesnt work

[VasVac]

I need to make a square column.  I must use tube command but it just do nothing. 

[Laszlo Nagy]

There is another approach and it is that you create a box, which is the bounding box of your intended Column, then drawn the section profile that needs to be cut from that shape to achieve the intended geometry. Then you just create extrusions of this profile on all sides of the Column and Subtract their bodies from the Bounding Box shape to achieve desired column geometry.

I hope this explanation makes sense. Think of the way a sculptor removes material from a piece of rock to achieve the desired shape.