I'm learning Rosetta now, when I browse the files, I find that Rosetta's database stores some params files, like 1.3.5_trisbromomethylbenzene_symm.params (in /Rosetta/main/database/chemical/residue_type_sets/fa_standard/residue_types/crosslinker), it contains several V* atoms, and I have trouble understanding the meaning of it. There is also a non-symmetric version of it, named 1.3.5_trisbromomethylbenzene.params, but it still contains virtual atoms.
I am wondering how to generate a file containing with these virtual atoms, and how to make a symmertric version of it.
Any suggestion would help me a lot. Thanks very much!