are u or your company able to get Subscription on max8? If so ProBooleans would probably take care of this easily. Great new Boolean & Cutter tools THAT REALLY WORK!!! And you can animate the cutters easily. Check out the vids on their website.
From traditional Booleans, higher res to start with can help sometimes, or as otherwise mentioned, Opacity maps in max or even in the compositing software--combustion, AE or Fusion would also do a reasonable job, depending on the "3D' nature of the results you are after?
They have been (until ProB's) a real pain tho often!)