RPG damage calculation formula.

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9 comments, last by dsage 19 years ago
I'm out of ideas at the moment. I'm working on the battle engine for my simple RPG, and I'm not sure how to calculate damage. The variables involved are attack, strength, defense, and position (I did say simple) Attack is the attack value of your equipped weapon, defense is the armor value of your armor. Position can have 3 values, forward, back and center (0, 1, 2) where forward means you're closer to the enemy, back means you're at the back of the map, and center is the default position. Forward: weapons do 50% more damage, you take 50% more damage Back: weapons do 50% less damage, you take 50% less damage Center: Everything does 100% damage, you take 100% damage My first damage formula idea was Damage = (strength + attack) - (enemy strength + (enemy armor / 2) ) Any suggestions?
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(enemy armor / 2)
That one confuses me a bit in the sense of "Why?" Why not just make all of the enemy armor values halved.

Anyways, this depends on the complexity of the game. For me, the Attack-Defense-Magic-Speed scheme was always just fine.

if player.row = front row_modifier=1.5
if player.row = center row_modifier=1.0
if player.row = back row_modifier=0.5

Damage = random(0.9, 1.1) * ((player.attack * row_modifier) - enemy.defense)

And then, whenever you equip a weapon or whatever, all of your stats get increased (or decreased) by the weapon's four stats. Its easy, people get it.

Some people like D&D rules however.
william bubel
That looks like it would work well, and I'm not quite sure what the D&D method is (Having never played D&D)
- - - - - - - - - - - - - - - -I am you and what I see is me
Quote:Original post by Geno the Great
That looks like it would work well, and I'm not quite sure what the D&D method is (Having never played D&D)


You could have a look to the D20 SRD (and you could even use it: it is distributed under the Open Gaming License, which is rather liberal).

Basically: any creature has an armor class (AC) ranging from 0 (very very bad) to +inf, 10 beeing 'no armor at all' on a basic human. To hit a creature, you must roll a d20 and add your attack bonus to the dice. If the result is >= creature's AC then you hit. The damages are dependant upon your weapon and some other factors (your force, the weapon type (magic, non magic) and so on). This oversimplified system hides a lot of details but is rather quick to play. It is more adapted to a pen & paper rpg than to a cg rpg (computer can do more precise calculus in less time, so why bother?)

Regards,
Quote:(computer can do more precise calculus in less time, so why bother?)


There's always the KISS philosophy. Keep your systems only as complex as they need to be to accomplish your goals. If your goals are a simple combat system, then this would be an excellent option. If your goals are a realistic, intricate combat system, then something more complex is necessary.

For any combat system, there are two fundamental stages that are necessary. Determining hit or miss, and determining damage done. Beyond that, you can add any number of additional features to reach the level of complexity you wish to achieve.
Please, stay away from D&D. It's horrible, and uses awkward numbers so that it can be played with dice, and so that players can do quick calculations in their heads. Things are not very sensible, objectively.

My first piece of advice is stick to, as the previous user said, keep it as simple as possible. Complex formulas and weird numerical ranges aren't going to make your game any better, but will make it harder for you to make sense of what different values mean.

I would suggest using a system based off of one number, like . . oh, how about 100. So, every attribute can range between 1 and 100, giving you an easy gague of how powerful things are. Strength of 80? Pretty good. Armor of 20. Horrible. Be sure to consider things like magical affects when considering these stats.

The exception might be something like HP, as you may want to increase it beyond 100.

Also, try to establish standards. Maybe make your base armor value for someone who is not dressed at all, and is not evading. Then you can build your armor ratings for different kinds of armor off of that value. Same for weapons - maybe the base is hand to hand combat.

The reason I suggest that you stick to a static range is because it helps simplify things later. That is, you may continue to expand the number of stats as the game gets more developed, and you may think "Wait. . . was running ranged from 1 - 15? Or was that attack, and skills range from 1 - 25."

Just some ideas. Oh, and avoid the D&D system!

--Vic--
Work backwards. Damage formulas are irrelevant when taken out of the context of the statistic that they apply to. 1000pts of damage is nothing if your average kitten has 2464789457906356 hit points.

So: how is health/resilience measured in your system? How much does it start off at, how quickly does it improve, if at all?

Then: how many 'average' blows should a character take before dying/losing?

Then: how much variance would you like each blow to have, from the average, if any at all?

Penultimately - how much of this variance do you want to come from random factors, how much from defence, armour, or skills?

Lastly - you now have a few numbers, desired average values and ranges etc. - look at how the stats you want in your game can combine to meet this goal.
Quote:Original post by Roof Top Pew Wee
Please, stay away from D&D. It's horrible, and uses awkward numbers so that it can be played with dice, and so that players can do quick calculations in their heads. Things are not very sensible, objectively.

My first piece of advice is stick to, as the previous user said, keep it as simple as possible. Complex formulas and weird numerical ranges aren't going to make your game any better, but will make it harder for you to make sense of what different values mean.

I would suggest using a system based off of one number, like . . oh, how about 100. So, every attribute can range between 1 and 100, giving you an easy gague of how powerful things are. Strength of 80? Pretty good. Armor of 20. Horrible. Be sure to consider things like magical affects when considering these stats.

The exception might be something like HP, as you may want to increase it beyond 100.

Also, try to establish standards. Maybe make your base armor value for someone who is not dressed at all, and is not evading. Then you can build your armor ratings for different kinds of armor off of that value. Same for weapons - maybe the base is hand to hand combat.

The reason I suggest that you stick to a static range is because it helps simplify things later. That is, you may continue to expand the number of stats as the game gets more developed, and you may think "Wait. . . was running ranged from 1 - 15? Or was that attack, and skills range from 1 - 25."

Just some ideas. Oh, and avoid the D&D system!

--Vic--


I mostly agree with everything, but I have to recall you that the D20 system has been successfully used in some AAA games (NWN, KOTOR, TOOE, and so on). It will also be used in D&D online and in the upcomming DragonShard. Therefore I guess that it is OK to use it in a game. Its main strength comes from its game logic. While it looks weak an unprecise, it contains multiple modifiers that completely change the most basic actions. Another strength - which is very important: it is already balanced :)

Regards,
I like the "out of 100" idea, that seems very reasonable. I'm thinking HP will start at 100 and your max HP will be 1000. Right now I want to focus on working on the battle interface.
- - - - - - - - - - - - - - - -I am you and what I see is me
Yes, I will definitely agree that the D&D system has been play balanced for quite some time - I think D&D's been around for quite a few decades, and the many revisions have probably improved the balance.

However, one problem with the D&D system is that if you use it, you are stuck with a D&D type game, more or less. That is, games like Final Fantasy or Zelda wouldn't work with a D&D system.

I really like Kylotan's suggestion as well. The numbers really mean nothing. . .in most cases. I still don't understand why people obsess so much about stats in modern RPGs. I think it should be about the battle system, story, environment, . .. I'm getting of subject really fast here, aren't I. But yeah, definitely think of how you want the game to be made. Just like drawing, you start with the skeleton of the body in the pose you want it to be when the drawing's finished, not with a really detailed nose.

--Vic--

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