QUOTE(mgajewski @ Sep 25 2007, 11:58 AM)
I was hoping for some devilishly clever trick. I know this is a real challenge.
It should be quite simple. All you need is a piece of facetted geometry, which can be done like this:
1. add a sphere (which *is* a revolved sphere and contains the facets you want)
2. export this sphere to *.OBJ format (facetted geometry, which retains quad faces instead of triangulating them)
3. re-import this OBJ file (which still is a solid you can use boolean tools on)
4. cut the portion you need (from the sides, not top or bottom)
5. difference a smaller sphere from the rest.
Attached is a file I created using an other application (which directly supports facetted geometry, without using the ex-/import route), but in IC it should work exactly as described above :-)