Die rollers openrpg does pretty well as part of core.
OpenRPG help and documentation sadly sucks as the developers have the choice of fixing bugs adding new features or doing documentation and you can bet you know which seems least fun and least immediate use to anyone.
However have you tried ever typing in "/help" to the chat line you will see a list of slash commands (amd slash aliases which are just commands again). The core set includes one called /dieroller. it doesn't say much about how it works exactly, so you type /dieroller without any parameters. When I do this I get:
Quote:
Available die rollers: ['std', 'gurps', 'd20', 'runequest', 'srex', 'shadowrun', 'sr4', 'wod', 'hero', 'wodex', 'trinity', 'hackmaster']
You are using the "std" die roller.
So 'std' is fine for d20 (and actually has a lot of tricks as standard that mean you can probably use it for these other game systems) but there are various other choices. So let's say you want to try WoDEx which I assume is World of Darkness Exalted?
So great but what now? sadly I have little to no idea. I would have to ask a person who uses that dieroller or examine the code line by line. There's some help in game if you go to the tree and ringth click the root and select, "Insert Features Node" (incidentally well worth exploring the feature's node for other things if you haven't already), and then when the new node "OpenRPG+ 1.7.1" (shows how old this is) arrives open it and double click on, "Load Die Roller Notes". Now open up the "Die Roller Notes" folder and there is a small -- very small -- amount of documentation.
You can also get some dieroller clues from going to the old OpenRPG Users Guide link at the top of the "OpenRPG+ 1.7.1" features node, that opens a web page (this one):
http://openrpg.wrathof.com/faq1/FrontPageAnd it has something on die rollers too.
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But like I said; it's far easier to find someone else who plays those game systems already (I do not) and ask them what they do. They'll likely have not only the answers to your questions but to questions you didn't even know to ask. I know Mayhem has groups that play those other systems.