3D nesting?

Hello.  I work with packaging, mainly thermoformed clamshells.  At my company, we use a program called TOPS to figure out how many items will go in a master carton and how many master cartons will fit on a pallet.  This works great if you are only dealing with rectangular boxes.  Irregular shapes, like clamshells, pose a problem.  TOPS only recognizes boxes and a few other shapes that have alreay been programmed into it.  For clamshells, we have to figure out how many will fit in a box manually.  I am looking for some kind of software that will take a Solidworks part and figure out how many of that part will fit in a box and in what orientation.  I know there is 2D software that does this for the CNC industry, but I am not aware of anything that will do this in 3 dimensions.  Anyone have any ideas?  Thanks.

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