# How to convert d20 battle sys to jrpg style?

Discussion in 'RPG Maker MV' started by watermark, Oct 13, 2018.

1. ### watermarkVeteran

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I'm terrible at math so someone help me out here. I want to find a good way to convert d20 stats to jrpg stats, mainly the hit accuracy part. Damage is more straight forward.

In d20, hit/miss is generally a 1d20(random num between 1-20) plus attack bonus versus the target's AC (some number, say 15). So in the simplest terms, if you roll higher than 15, you hit the target.

In JRPG systems it is attacker hit% versus defender evade%. Basically what the rpg maker default sys uses.

So how can I convert d20 attack bonuses and AC to hit% and evade%? For example, how much hit% does a +1 add? What evade% would AC of 15 equal?

Head smokin from too much math...

2. ### gstv87Veteran

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you *can* go into the program's code and change the percentage to integer, as simple as that.
there shouldn't be any conversion involved,.... just find the calculation and set it to whatever you want.

3. ### PorygPixie of the Emvee kingdom, Ham of a Hamster

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It's a pretty simple math. We have a d-20 of which you have 5 that will strike. That's equal to 5/20 accuracy, in otjer words 1/4, in other words 25%.
Increasing the AC by 1 would mean 16/20 will miss, in other words 1/5 will hit, in other words 20% accuracy. And instead of increasing the AC if you were to increase the d-20 by 1, it's 15/21 miss, therefore 6/21 hit, after simple maths it's 2/7, which is equivalent to 28,181818... % accuracy.
We're throwing two numbers against each other, from which you can take inspiration. Take either hit accuracy or dodge... And make it 100% or 0% respectively. If you made 0% dodge, you'd need then a 25% skill accuracy. Accordingly if you gave a skill 100% accuracy instead of giving enemies 0% dodge, you'll need to give enemies 75% dodge.

4. ### gstv87Veteran

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not always.
that depends on the setting of the battle and the characters involved, which is all based on integers.

the d20 is just a mean of randomization.

5. ### KesGlobal Moderators

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'Game Mechanics Design' is for talking about aspects of gameplay at a more conceptual level. "How do I. ..?" (implementation) questions belong in the Support forum for the engine you are using.

6. ### PorygPixie of the Emvee kingdom, Ham of a Hamster

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@gstv87 I was basing off what the OP put in their OP as an example.

7. ### loki2007Villager

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You're over thinking probably. Think of accuracy as: (I'm oldschool thaco, so...)

at level 1 eveyone needs an accuracy roll of 100% to hit a def of AC 0 (which would have been a 20)
therefore 5% accuracy equals one digit on a d20 die roll.
1=5%
2=10%
3=15% etc.