[Guide] How Skill Boost Gain Works

Discussion in 'Guides' started by Kivanc, Dec 2, 2014.

  1. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    Hi everyone,

    This guide will be the first of many guides that are possible thanks to @jnalyz's contributions to the forum. All information provided below is extracted by him/her and used with his/her permission.

    Before anyone attempts, let me also stress that none of this information is gained by hacking the game. It is decompilation and examining the source code. Any discussion or attempt of hacking / modifying the source code is strictly prohibited and will result with banning. These guides are created to increase our knowledge about the game. All information on these guides can also be approximated by gathering data community-wise and then examining this data.

    If you are a picture guy, here is the story version of the guide, thanks to the contributions of @Person Man and @Rexlent:

    [​IMG]

    How Skill Boost is Gained
    As we all know, every time a character activates a skill in a battle, there is a chance that this character will gain a skill boost. But how does the game compute this?

    Formula
    The game uses the following formula to compute the probability of getting a skill boost.
    For a character and for a phase (more on this later):
    Code:
    P(skill boost) = 0.02 / MIN(base probability of all skills activated on this phase).
    
    English translation: Get all skills that are activated by that character. Filter the ones that are for the current phase (more on this later). Get the base probability of the skill that has the lowest base probability. Divide 0.02 by this number. Round down to two decimal places. I.e., when looking at the percent, drop everything after the decimal point: 6.67% becomes 6%, 2.2% becomes 2%, etc.

    Example
    Bahl's Gigasword and Megasword skills are both "attack" phase skills.
    Code:
    If Bahl activates both these skills, P(skill-up) = 0.02 / 0.4 = 0.05 = 5%
    If Bahl activates only Gigasword = P(skill-up) = 0.02 / 0.4 = 0.05 = 5%
    If Bahl activates only Megasword = P(skill-up) = 0.02 / 0.5 =  0.04 = 4%
    
    How to use this information?
    Well, unless your characters skill boost level is 0%, it is ALWAYS better to select skills with lower base activation rate for skill boost farming. For example: Bahl, skill boost level: 50% Skills: Megasword vs. Gigasword.
    Code:
    Megasword activation rate: 50% + 50% = 100%
    Gigasword activation rate: 50% + 40% = 90%
    
    P(skill-up, megasword) = 1 (guaranteed activation) * (0.02 / 0.5) = 0.04 = 4%
    P(skill-up, gigasword) = 0.9 (activation rate) * (0.02 / 0.4) = 0.045 = 4.5%
    
    Conclusion: selecting gigasword increases your chance to get skill boost compared to megasword.

    Note: If the character is at 0% skill boost level, the probability of getting a skill boost for all skills are the same (balanced with activation rate)

    The second way this affects you is that once you reach guaranteed activation for a particular skill for a phase, there is no need to include other skills of the same phase while skill boost farming. For example, Bahl's Terasword and Attack 10%+ (first job) skills both have 30% base chance and they are both attack phase skills. So, if your Bahl has 70% SB, then selecting only one of these skills is equal to selecting both since both skills will activate at all times, however skill boost gain probability for attack phase will be calculated only once.

    Phases
    This section is not finalized yet as the code is messier. Currently, there are three known phases where skill boost calculation is done: attack, heal, and counter attack. At this point, we don't exactly know which skill belongs to which phase, however it is in general possible to approximate by watching when the skill is activated in-game. For example (all approximations):
    • Attack phase: Any skill that deals direct damage to the enemy, any skill that buffs the character.
    • Heal phase: Any active heal skill or any remedy skill.
    • Counter attack phase: All counter skills and capsule generations.

    In other words, for each character that managed to activate at least one skill that belongs to each phase, a separate probability of skill boost is calculated.

    How to use this information?
    If a character has skills from different phases, it is ALWAYS better to equip different phase skills (and the ones with lower base activation rate) instead of same phase skills.

    For example, for Yukken's Negotiator Pro (30%, attack), Teraspear (30%, attack), Self-heal (30%, heal) skills, if you can only get two of them, you should select one from attack phase and Self-heal since when Yukken is 0% SB:
    Code:
    P(skill-up, Negotiator Pro + Teraspear) = P(skill-up, Negotiator Pro) + P(skill-up, Teraspear given no Teraspear) = 0.3 * FLOOR(0.02 / 0.3) + 0.7 * 0.3 * FLOOR(0.02 / 0.3) = 0.018 + 0.0126 = 0.0306 = 3.06%
    P(skill-up, Teraspear + Self-heal) = 0.3 * FLOOR(0.02 / 0.3) + 0.3 * FLOOR(0.02 / 0.3) = 0.018 + 0.018 = 0.036 = 3.6%
    
    The situation becomes more dire when Yukken has higher skill boost level initially, let say for 70%:
    Code:
    P(skill-up, Negotiator Pro + Teraspear) = P(skill-up, Negotiator Pro) = FLOOR(0.02 / 0.3) = 0.06 = 6%
    P(skill-up, Teraspear + Self-heal) = FLOOR(0.02 / 0.3) + FLOOR(0.02 / 0.3) = 0.06 + 0.06 = 0.12 = 12%
    
    Additional Notes
    • It is confirmed that the maximum skill boost you can gain per character in a dungeon is 0.2%.
    • It is confirmed that equip skills (skills with no activation rate since they are passive buffs) do not get any chance to get skill boost. In other words, they are useless for skill boost farming.
    • Capsule usage might affect skill boost gain (either as a part of existing phases or as a new phase) but we are not sure about this.

    Contributors
    Guide compiled by @Kivanc. All data is extracted by @jnalyz and used with his permission.

    Disclaimer
    Mistwalker can change the algorithm used to compute skill boost gain rates at any given time with a direct or stealth update. Although we will do our best to update the information when such an update happens, Terra Battle Forum takes no responsibility due to potentially stale information provided in this guide.

    You can use the information provided in this guide in another web site, providing that the content is not changed and proper credit given to myself, @jnalyz, and this forum.
     
    Last edited by a moderator: Nov 12, 2015
  2. legaiabay

    legaiabay Active Member

    Messages:
    191
    Likes Received:
    59
    Joined:
    Oct 11, 2014
    Very nice information! I need this so much. I confused with how SB% works. So for best result, just using one skill with lower base activation each phase? If I using much skill (example : my Ma'curi has 5 skill in one phase), which better?
     
  3. Dlacsjwh

    Dlacsjwh Member

    Messages:
    173
    Likes Received:
    26
    Joined:
    Sep 18, 2014
    Very nice!
    This seems to confirm my suspicion that lower proc rate gives higher chance of skill boost and that the phases are calculated separately.
    As for phases, I think there are four.
    Attack Phase
    Heal Phase
    Capsule Phase
    end of turn/beginning of turn? (I've only experienced this with status cure skills like panacea, Espirit de corps...etc) - I'm not sure if this is even a separate phase but characters can boost after the mobs for the next stage has spawned, but before you make any moves. This is very strange since cure skills are cast at the heal phase. It could also be just a graphical delay as well.
     
  4. NinthGhost

    NinthGhost Well-Known Member

    Messages:
    598
    Likes Received:
    325
    Joined:
    Nov 5, 2014
    Medals:
    With this everyone will become a skill boost ninja. Hi yah!
     
  5. Chev4

    Chev4 Active Member

    Messages:
    550
    Likes Received:
    248
    Joined:
    Oct 14, 2014
    Doing some grinding, and have immediately changed my character setup; This would explain SS mages' abnormally high skill boost rate and confirms the other guy's suspicion about skill boost rate and intial ability rate.
     
  6. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    If you don't have any alternatives, using 5 or the one with the lowest activation gives the same results. For example, let's say that your character has 70% initial SB, meaning that he will activate all skills guaranteed (with base rate 30% and up), now for the same phase, it does not matter whether you include all skills or just one with 30% activation rate, since in all cases your skill boost gain chance will be:
    0.02 / 0.3 = 0.067 = 6.7%

    However, if your initial SB is 60% and it is not guaranteed to activate the 30% SB chance (base) skill, then having other skills with guaranteed activation on the same phase does help since in case you don't activate the 30% chance skill, then you will get a lower skill boost gain chance from the higher base activation skills you are guaranteed to activate.

    Does this answer your question?

    Thanks! We are still a little iffy about the actual phases and which skills go to each phase. We are trying to get better information about this. The three phases above are verified from personal experience and in game data, but yes, there might be more.
     
  7. Dantelynx

    Dantelynx Active Member

    Messages:
    129
    Likes Received:
    128
    Joined:
    Oct 21, 2014
    First, thanks for the AWESOME job :)
    Just was wondering if Alika's and Palpa's regen skills are included in the heal or attack phases ?
     
  8. Cel

    Cel Well-Known Member

    Messages:
    704
    Likes Received:
    280
    Joined:
    Nov 27, 2014
    Yay, thanks for all the data. It's an interesting approach to skill boost, but it also makes sense. Now, I can figure out which one of my characters will get, on average, the worst skill boost, as to prioritize them first. And, I also know the pain, of how difficult it can be to skill boost certain monsters not in the PoF without Negotiator. From a skill perspective, characters with attack/buff, heal, and capsule skills can gain the most skill boost. Attack/buffs seem to be around 30%, heals are usually high, unless it's a Mega Heal, Self at 30%, and Capsules are always at 30%. That can add up to a lot of skill boost.

    I feel Counterattacks are too unreliable for skill boost =(.
     
  9. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    As I mentioned that part of the guide and data collection is still iffy but we think that it is "heal" phase.
     
  10. legaiabay

    legaiabay Active Member

    Messages:
    191
    Likes Received:
    59
    Joined:
    Oct 11, 2014
    So with all 5 skill activated at once, it will choose one with lower activation as base probability? As you said that both Megasword and Gigasword activates and still counted 30% for base probability.
     
  11. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    Yes, the lowest base probability of all skills activated in a turn in used in the formula. For Megasword (40%) and Gigasword (50%) , it would be 40% base probability (I think this is what you mean, but I am double checking because you said 30%).
     
  12. Cel

    Cel Well-Known Member

    Messages:
    704
    Likes Received:
    280
    Joined:
    Nov 27, 2014
    Some characters have skills that aren't the default percentage (50% - Mega, 40% - Giga, 30% - Tera). Zan's Megasword, has a 30% activation rate, which I presume means it has a higher chance to give skill boost, compared to other sword user's 50%, Megasword?
     
    Kivanc likes this.
  13. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    Oh, I apologize. Yes, the only thing that matters is the base percentage. I believe that this skill is AOE, is that the case? (Generally the skills have lower percentage with the same name skill when this is the case)
     
  14. legaiabay

    legaiabay Active Member

    Messages:
    191
    Likes Received:
    59
    Joined:
    Oct 11, 2014
    "Get the base probability of the skill that has the lowest base probability."

    Damn, I didn't read that sentences. I'm too focused with the formula -_- Sorry about that.
     
  15. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    No worries. I tried to provide the Math formula (well as much as I can) and the english translation as well :)
     
  16. Cel

    Cel Well-Known Member

    Messages:
    704
    Likes Received:
    280
    Joined:
    Nov 27, 2014
    It's not the case for Zan (Sword w/Fire+Ice attacks) and Sh'berdan (Spear w/Light + Dark attacks). I think there are some oddities, but in general, they are AoE (Grace's Megabow, Area (1)). Someone else has like a 65% Mega-skill too, that I don't think is an AoE, but until I can get the character to confirm myself, I'll have to check the wiki or other websites to check, and even then some are wrong.
     
  17. mnov

    mnov Active Member

    Messages:
    161
    Likes Received:
    38
    Joined:
    Oct 24, 2014
    I think it is possible that equip skills with no percentage also activate skill boost. I've seen it twice that Kuscah gets a skill boost at the start of a turn although I don't remember if he was in the first job or not (they happened lategame so there is a good chance it was not the first job). If anyone else can confirm this, that'd be great.
     
  18. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    Interesting. From our data, I can verify that Zan's skill is indeed 30% activation rate (which was well known) without any extra effects.

    I forgot to add this to the guide. It is actually confirmed that equip skills DO NOT get any chance to gain skill boosts since they are never activated. They are passive buffs that apply to the character even if the character does not attack at that turn. The thing you observed is probably an additional phase that we haven't figured out, or something like capsule usage. We are working on the details.
     
  19. Bearauder

    Bearauder Active Member

    Messages:
    481
    Likes Received:
    129
    Joined:
    Oct 9, 2014
    Question, so...this guide is only useful when you wanna boost your unit after lv35, before lv65?

    Am I right to say that, if you get 65 on most of a unit jobs then when you are boosting you probably will equip all the skills that can proc, which diminish how well this guide will help?
     
  20. Kivanc

    Kivanc The Data Keeper

    Messages:
    2,059
    Likes Received:
    1,048
    Joined:
    Oct 30, 2014
    Depends on the character.

    For Bahl, e.g., all of her skills are attack phase skills, so it does not matter much. However for a character like R'zonand, who gets one of the most important skills for skill boost (Restorative Counter) on Job 1, L65, or who has Heal with 30% base activation rate on job 3, L30, you might want to optimize the selected skills to speed up the process. Our previous belief on this topic was mostly that the more skills you activate, the better your skill boost gain is. It turns out that this is not true, and it is actually not good to select all 100% heal skills since they are activated in the same phase and give little skill boost chance. This guide basically gives you a way to evaluate your currently available skills (how good they are for skill boosting) and whether you want to go the extra mile to enable higher level skills (especially L65) since they might increase your rates. In my previous guide e.g., I was suggesting to only enable skills up to L30 since they are easier to enable and has higher base activation rate.

    Also, this guide provides you a better understanding of something that we thought was random in the game. Knowledge is power, my friend :)
     
    xAobax and Bearauder like this.

Share This Page