Core mechanics of VX Ace

[Emperor Xan]

Okay, I tried doing a search and couldn't find what I was looking for in regards to the core mechanics of the game's default engine.  Specifically, I'm looking for the various formulae used to calculate changes of doing anything.  For instance, what is the default chance to hit a target whose defense is the same as the attacker's attack chance?  How does strength or agility play into these formulae?

Thanks in advance.

 

[kerbonklin]

You would have to look into Game_BattlerBase for parameter-definitions, and Game_Action + Game_ActionResult for how most of the things play out. Some stuff is in Scene_Battle as well, like checking flags.

If you are using the Lite version of Ace, you don't have access to scripts at all.

Using Ctrl + F or Shift + Ctrl + F will help you search anything you need in the scripts, as well as the F1 Help File.

- Normally Agility is used to determine an action's Speed, how fast a battler performs their action compared to an opponent and the rest of your allies. And it also plays into escape rates and preemptive/surprise encounters as well.

- Defense has nothing to do hit Hit Rate or Evasion unless you change it to do so. Hit Rate and Evasions are calculated separately upon action processing, Hit first and then Evasion second. (both cap at 100%, I think it's coded in Float)

- Attack and Magic Attack parameters are only used in damage formula functions by default, if a skill refers to them. All normal parameters (the 8 from the Class tab of the database) are integer values.

A skill's damage formulae can refer to any parameter of a subject involved (a for attacker and b for target)

For example the default ID 1 Normal Attack is "a.atk * 4 - b.def * 2" which means the damage dealt is the attacker's attack parameter * 4 - the target's defense parameter * 2.  You can always do things like a.agi (for agility), a.hp (for current HP), a.mmp (for max MP), and so on.

 

[Archeia]

How about this one? :'o

 

[Emperor Xan]

Okay, maybe I need to reword the question.  I'm looking for the core mechanics that look similar to  Dungeons & Dragons 3.5's core mechanic (attack target number to succeed is d20 + str bonus + base attack bonus vs. 10 + armor + dex bonus + misc).  Given that the average roll of a d20 is 11.5, I can figure out the bell curve from there (d20s have 5% incremental values).  As a game designer, I get the math and the probably mechanics needed to make a game work as an unpredictable system that has finite bounds and I can decode the probability distribution with that information so that I know what sorts of experiences I can design.  My weak point is in reading code.  Designers don't normally have to do that.  My strong suit is in story, setting, and rules design, which rely almost purely on language and dice codes with attendant modifiers.  Even card game mechanics have a similar spread when you're designing them.  They just don't get so buried in code.

 

[Engr. Adiktuzmiko]

so are you asking for a script that will change the default system to that?

 

[Andar]

Okay, maybe I need to reword the question.  I'm looking for the core mechanics

OK, first to clear up a few misconceptions ;-)

Most Parametes (as opposed to SP-Parameters and EX-Parameters) have no core mechanic, but only a default mechanic.

ATK, DEF, MAT and MDF are NOT used in any part of the game's scripts or core engine. The only place where they're used is the default damage formula placed in the skills, and that formula can (and often is) modified by the developer without ever touching any part of the programming.

If you combine that with the option that the parameter values can be anything from low numbers to several thousands, that should make it clear that it's the game developer who designs that part of the mechanics, he's only given a few default values to test (and those default values and default skills aren't exactly "balanced" in my opinioin).

LUK and AGI are the only parameters that have a "core mechanic", and even that is only minimal - AGI being the base number for the action speed and the order in which the skills are executed in default battle, LUK influencing the chance of being inflicted by a state or loosing it.

SP- and EX-Parameters have functions ingame - the more important ones of those parameters have their mechanic described in the Flowchart Archeia linked a few posts above.

But they are all percentage-based and more or less independant from each other. For Example, HIT is the percentage that determines the chance of a physical attack hitting the target. If the W%-Roll is below that number, the skill hits - if not, it misses. There is no modification by enemy for that roll, only the actor's own equipment can change the hit%.

After the hit, the enemy has a chance of evasion - that is another, different W% on the EVA value.

Other SP/EX-Parameters simply change the damage rates to simulate weakness or resistence, add regeneration rates or determine the chances for target selection and so on, but almost every value is independant of each other, only effecting that specific part of the engine.

Edit:

To make it more clear, ATK is (in default) a number that determines the damage done to the target, and weapons simply add ATK to increase the damage. DEF is used to reduce that damage in default, and armors add to DEF to reduce the damage. Neither value is used to determine hit percentages in default.

 

[Xypher]

not completely related but the average roll of a 20 sided die would be 10.5 not 11.5

 

[Emperor Xan]

Whoops, that's what I get for trying to write something so late at night.

OK, first to clear up a few misconceptions ;-)

Most Parametes (as opposed to SP-Parameters and EX-Parameters) have no core mechanic, but only a default mechanic.

ATK, DEF, MAT and MDF are NOT used in any part of the game's scripts or core engine. The only place where they're used is the default damage formula placed in the skills, and that formula can (and often is) modified by the developer without ever touching any part of the programming.

If you combine that with the option that the parameter values can be anything from low numbers to several thousands, that should make it clear that it's the game developer who designs that part of the mechanics, he's only given a few default values to test (and those default values and default skills aren't exactly "balanced" in my opinioin).

LUK and AGI are the only parameters that have a "core mechanic", and even that is only minimal - AGI being the base number for the action speed and the order in which the skills are executed in default battle, LUK influencing the chance of being inflicted by a state or loosing it.

SP- and EX-Parameters have functions ingame - the more important ones of those parameters have their mechanic described in the Flowchart Archeia linked a few posts above.

But they are all percentage-based and more or less independant from each other. For Example, HIT is the percentage that determines the chance of a physical attack hitting the target. If the W%-Roll is below that number, the skill hits - if not, it misses. There is no modification by enemy for that roll, only the actor's own equipment can change the hit%.

After the hit, the enemy has a chance of evasion - that is another, different W% on the EVA value.

Other SP/EX-Parameters simply change the damage rates to simulate weakness or resistence, add regeneration rates or determine the chances for target selection and so on, but almost every value is independant of each other, only effecting that specific part of the engine.

Edit:

To make it more clear, ATK is (in default) a number that determines the damage done to the target, and weapons simply add ATK to increase the damage. DEF is used to reduce that damage in default, and armors add to DEF to reduce the damage. Neither value is used to determine hit percentages in default.

Okay, so where are these equations in the program?

 

[Engr. Adiktuzmiko]

For ATK,MAT,DEF,MDF... as they all said, they are only used in the damage formula box (the box in the skills tab where you input the formula for damage)


for the others, try looking at Game_Battler or Game_BattlerBase