I'm not trying to cause controversy here, but if all you want to do is export a sphere model you can do so from Wings3D. I think it is great that Bryce6 will now export booleaned primitives, but if all you need is a primitive, Wings has quite a few types available, and it will export them in several different file formats like .3ds, .obj, FBX etc. Wings is also free so it makes a good accessory to Bryce.