How to create a hollow tower/tube

• This is quite vague, as it is very difficult to explain without pictures (you could check out this video - Thanks to Runescapedj - hope its ok me using the video!)

• Extrude a selection the size of the tube you wish to create.
• Use q and scroll to make the sides rounded into a cylinder, like the video shows.
• Select as much of the the top part of the cylinder as you can, without selecting the cubes you have altered by using q and scrolling. *Now cut away (intrude?) the selection. If this isnt exactly what you want, use the same technique as above to curve the inside.

• Alternatively, make a mapmodel of what you want and import it. (very VERY easy with Wings3d)