Monday, March 29, 2010

Fantasy versus Historical in rules design

I was reading a blog the other day( , Its quite interesting to read) and a discussion (a bit older there) touched upon the AC system being a good representation of how armour works, as armour does primarily deflect blows not absorb them (in the manner of damage reduction). While I use damage reduction for armour his point was very well thought out and explained.

The AC system in OD&D (and still used) does a good job of simply and quickly matching up armours effect in a historical context. I disagree with using AC in that manner in my games because I do not run a historical game but a fantastical one, and while in many cases this is the same there are big differences.

If we look in this one instance if the DR is modelled right the AC benefits from armour and the DR from armour should work out about the same benefit from two warriors slogging at each other with swords. The AC system is quicker to resolve and better, case closed lets choose AC right? in a historical game yes, in a fantasy game no. How does armour protect you versus a sword of sharpness? or a 50 tonne piles of supernatural dragon muscle swinging a claw around? or a magical staff of shocking? or an ogre throwing boulders? or the mighty firearm that made armour (eventually) passe? In these cases the DR model now begins to work better. The armour can be modelled to slow you down but absorb any of the blows a normal swordsman could swing, yet against the thrown boulder the unarmoured swashbuckler now has a better shot at getting out of the way.

This type of thought process needs to bleed through to other aspects of game design as well, to remember the difference between the historical model and the fantasy or mythical model. This is probably the easiest thing to overlook (I do it myself all the time) and really dates back to the question of asking yourself "How could I break immersion with this rule".


  1. Additionally, modern ballistic weaves, plates, and inserts so absorb and dissipate rather than deflect, so the DR-model is more technically correct than the AC-model for those types of protective gear. :)

  2. I think it also depends on how you want armour to behave out of combat. Does it defend against traps, or falling in a pit? What about a sniper?