> If I have a source directory full of random ROM files and destination as an
> empty directory will the rebuilder create as many rom sets as it can from the
> given ROMs?
>
> More imporantly will it ignore files that it cannot make complete sets out of?



The rebuilder is file based, not setbased. It takes a file from the source (or files inside zips), tries to match the crc32 and size (not the name) with the loaded datfile and -if a match was found- creates all (!) files in the destination. 'All files' means that if a single rom is used by 10 sets, all 10 sets are created with that one single rom. For the destination the correct set and filename is chosen.
So this automatically answers your second question: Since the rebuilder doesn't know about sets, you may get incomplete sets. But the file-based behaviour is just THE cool thing about the rebuilder. It's intended that way.

Roman Scherzer
ClrMamePro