Me again (have to back into work tonight so kicking heels at the moment)

The obj import is a red herring and also the more than one object idea. You can reproduce the problem by inserting the poser primative and shrink it done to 5% to get the same problem, you can duplicate the ball (i.e. two props) and the problem will still appear. If you insert another ball at 100% all three will render ok, as soon as you shrink the 3rd ball down to 5% the problem re-appears.