;| SHO.lsp -- Slice HOrizontal with just one point

SHO makes it easy to slice selected 3D solids horizontally in the
current UCS by picking just one point. Should work with all versions
that support 3D solids, although not tested below 2006.

Delete the "b" if you like being given the option of which side to 
delete. With the "b", both sides are retained.

by Bill Gilliss
bill at realerthanreal dot com
Comments and suggestions always welcome.

No warranty, either expressed or implied, is made as to the fitness of
this information for any particular purpose.  All materials are to be
considered 'as-is', and use thereof should be considered as at your own
risk.

v 1.0  2006-11-20 - initial release
v 1.01 2010-02-12 - ignores non-solids

Keywords: AutoCAD AutoLISP slice horizontal
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|;

(defun c:sho ( / ss)
  (prompt "Select solid(s) to slice horizontally: ")
  (setq ss (ssget '((0 . "3DSOLID"))))
  (if (> (sslength ss) 0)
         (command "._slice" ss "" "Z" 
            (getpoint "\nSelect point on horizontal cutting plane: ") 
            "_non" 
            "@0,0,1" 
            "b"
            )
         (princ "\nNo 3Dsolids selected.")
         )
  (princ)
);defun

(prompt "SHO loaded.")

(princ)