Cutting objects

[Foxbat]

I'm thinking about the best way to cut an object with an arbitrary cut
plane and then render it.  My first thought was to use feedback from
the geometry engine (orient my object to intersect a clipping plane in
the way I want then redisplay it as it is) however in the feedback 
section of the manual it seems SGI does everything but remove the section
to discourage you from using feedback.  So, has anybody done this?  Would
it be faster to write my own clipping routine on the host?  (We have
4D/220's and 240's - so they're fast machines)

Thanks,
Tim Hall