You got it.
But AD&D 2nd edition used the percentage for damage resistance. It wasnt just elemental either, you could also have physical damage resisitance, but it was very rare.
D&D 3rd edition started the whole 5/- thing for taking off points of damage instead of resistance. But in normal D&D 3rd you didnt have percentage resistance.
I've never played tabletop Star Wars D20 so I can only assume its something unique to their system.
OR, they added it just for the video game.
The problem is: I dont know which effect takes place first. Do they subtract the 5 points first and then apply the percentage? Or is it the other way around?
It probably doesnt matter too much but I'd like to know.
Incidentally, if you wanna know how their nomenclature works:
Damage Resistance 5/Silver means the person has all sources of damage reduced by 5 points, but silver overrides it. So if they were hit by a silver sword or arrow (or a magic spell that does physical damage and is of a silver source) then the resistance would not apply.
Another example: Damage Resistance 10/Fire. If the person were hit by a meteor strike (which I believe is half fire and half earth damage) then they would have the earth part of the damage reduced by 10 points, but the fire part does full damage.
Now the other way to make damage resistance:
Fire Resistance 5/- means the effect is ONLY applied to fire damage, but nothing special can pass through. That means if the opponent swung a silver sword enchanted with fire, it could not penetrate & ignore the resistance. The reciever has their damage reduced by 5 points. However, usually when a sword is enchanted with a short term spell after the fact, it still does its physical damage and a couple extra points of magic damage. Since a regular sword damage is 1-8 that would still apply, because its physical and not fire. The 1-6 points of damage applied from the flame effect would be reduced normally.
But a magical sword OF flame (like the one conjured by druids) is all fire damage and therefore all its damaged would be affected by the victims fire resistance.
In D&D, rarely do you see Damage Resistance 5/-. There is almost always something that can pass through the resistance, whether its silver, cold iron, dark wood, adamantine, magic, ice, fire, whatever.
Getting back to Star Wars:
I'm pretty sure the points dont stack, so if you have armor with a natural fire resistance of 10, dont waste your time putting in an upgrade that has fire resistance 5. It wont stack to 15 points, it will just take whichever one is higher.
Same with the belts and gloves and implants that offer damage resistance. They don't stack so don't go overboard while equiping thinking you will eventually be resistant to 50 points of damage.