Spiral Staircases

Now   select  one  of the  steps  and  lower it using the z-axis
window  until  it is level with the floor of your bounding box.
Now  lower  the  next brush using the same technique until
it lines up above the first step.  Repeat this process so that
you'll  eventually  have the  structure  pictured  below.


   

Once  the  stairwell  is  in  place  go ahead and make  a  new  brush
that  will  run  the  length of the entire staircase  down  the  center.
Make sure to leave some room at the top to allow for  an  exit.  Now
with the new brush selected choose the curves option and select
cylinder.     Cap  the  patch  normally   and   be  sure  to  line  up  the
texture by hitting 'ctrl+n'.  The next step now will be to enclose the
stairwell  by  creating  a  new  brush that lines up with the outside
borders  of  the  staircase  and  runs  the entire length.  Select the
brush  option  on  the  toolbar  with  the  new  brush  selected   and
choose  arbitrary  sided  with  a  value  of  at  least  20.

    

Now hollow  the brush.  Onwards and upwards!