I'm not sure if this is possible to do, but I'll present it in hopes of an answer. I assume this will require VBA code. I can place the VBA code in a module and run it, but that is the limit of my VBA knowledge.

I am trying to determine the most efficient yield.
The two sizes of raw material are 24 x 36" and 25 x 38". The actual useable space is 23.375 x 35.5" and 24.375 x 37.5" respectively.
We are cutting pieces of varying sizes out of the raw material. For example we may need a quantity of (25) 8 x 10s, (7) 3 x 5s and (4) 12 x 12s on a single job. The pieces can be rotated in any direction on the raw material and obviously more than one flat of raw material may be needed.
An automated CNC router will cut them out and it has some requirements. Because the router uses vacuum to hold the pieces down, small pieces don't hold as well and therefore more room needs to be allowed between those pieces for possible movement during the routing process.
If the thickness of the raw material is .064", any piece that it is more than 64 sq inches needs 1/8" between it an any other piece. If it is less than 64 sq inches then 3/8" is needed between it and any other piece.
If it's too difficult to determine varying distances of pieces within a flat, then use the worst case scenario. In this case that would be 3/8" between all pieces.
There are four thicknesses of raw material and obviously the thicker material has more weight and therefore holds down better and has smaller requirements between pieces. I can provide that, but it's not necessary to have all of that in one bit of code. If it makes things easier, I can make copies of the code and change in those distances to suit.
Assuming that it is possible to construct VBA code to determine the best yield, in what form can an answer be returned? In other words, if the pieces must fit in an odd arrangement, how will that be expressed?
Thanks for considering this unusual request. I realize that this is challenging.