It’s very simple right now: it will split all selected structural columns at a level elevation specified by the user (beta developed by Ken Marsh)
Download:
http://tiny.cc/ColumnSplitterBeta
Read post:
http://marshapi.com/1/post/2014/01/vertical-column-splitter-beta.html
Read previous related post (including dialog on bugs related to slanted columns and masking):
http://revitoped.blogspot.com.au/2013/12/split-column-wish.html