hi community
thanks andy+, */* worked fine.
but by doing this, the sub-folders under root level will still be created on the other peers. they are all empty. nothing inside them. just a bunch of empty sub-folders.
and then, if someone accidently delete or modify the empty folders on the peer sides, which were not allowed to be synced, then on the server side the original folders content lots of your important files, will also be deleted real quick. this is because resilio sync considered that folder is no longer exist and removed it. so leaving those folders to an amateur or someone you don't trust will make you in a big risk. be careful.
for me, if i had some files or folders don't wanna to be synced, simply prefix a ~ to these folders, and they will disappear like a charm on other peers. no need to add rules into the ignore file. just prefix a ~ to ignore. and you can use this mothed on almost any folder / files. have a try.
BR