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PSA: How interaction speed reduction calculations work

Orion
Orion Member Posts: 21,675
edited October 2018 in General Discussions

This is basic physics you should learn in high school, but many people have been having problems with it, so here we go. A decrease in speed of x% does not translate to an x% increase of time spent.

  • Interaction speed in Dead by Daylight, in the case of generators, healing, repairs, sabotage, and so on, is measured in charges per second (c/s).
  • Each interaction has a set number of charges required for completion. Healing, for example, requires 16 charges (16 c).
  • The base interaction speed is 1 charge per second (1 c/s).
  • To get the total interaction time, you divide the number of charges required by the interaction speed.
    • In the case of healing, it's 16 charges divided by 1 charge per second - 16 c/1 c/s = 16 s.
  • A speed reduction of x% means that the number of charges per second (the speed at which the interaction is completed) is reduced by that amount.
    • In the case of Thanatophobia, for example, if two people is injured you have a 9% speed reduction. That means that if you're trying to heal someone, you are only healing them at a rate of 0.91 charges per second (1 c/s - 0.09 c/s = 0.91 c/s). The total healing time becomes 17.6 seconds (16 c/0.91 c/s), which is a 10% increase in time spent.

I put the more important bits in bold, which should allow for a quick TL;DR read.

Comments

  • Khalednazari
    Khalednazari Member Posts: 1,433
    Thank you 😊
  • Khalednazari
    Khalednazari Member Posts: 1,433
    edited October 2018
    Also, most people get confused because players usually refer to these things in just one unit, and that is seconds (time). 
  • Killigma
    Killigma Member Posts: 372

    Where were you while I was studying Physics at high school Orion!

  • Orion
    Orion Member Posts: 21,675

    @Killigma said:
    Where were you while I was studying Physics at high school Orion!

    Probably learning physics myself.

  • Khalednazari
    Khalednazari Member Posts: 1,433
    Seems like I need to create more math questions for Dead By Daylight now. 
  • Orion
    Orion Member Posts: 21,675

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    No, you don't.

  • Killigma
    Killigma Member Posts: 372

    @Orion said:

    @Killigma said:
    Where were you while I was studying Physics at high school Orion!

    Probably learning physics myself.

    Not good enough, I now shift my lacking grade across onto you and from hence-forth it is your fault.

  • Khalednazari
    Khalednazari Member Posts: 1,433
    Orion said:

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    No, you don't.

    Default Dwight wants to come out of the closet. 
  • Killigma
    Killigma Member Posts: 372

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    Maths with Orion, every Friday at 11:00am GMT

  • Khalednazari
    Khalednazari Member Posts: 1,433
    Killigma said:

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    Maths with Orion, every Friday at 11:00am GMT

    👍 SOUNDS GREAT! 
  • Orion
    Orion Member Posts: 21,675

    @Killigma said:

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    Maths with Orion, every Friday at 11:00am GMT

    Orion has classes. I'm only at home today because I woke up wanting to throw up.

  • Khalednazari
    Khalednazari Member Posts: 1,433
    Orion said:

    @Killigma said:

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    Maths with Orion, every Friday at 11:00am GMT

    Orion has classes. I'm only at home today because I woke up wanting to throw up.

    Throw up your knowledge on us! 
  • Killigma
    Killigma Member Posts: 372

    @Orion said:

    @Killigma said:

    @Khalednazari said:
    Seems like I need to create more math questions for Dead By Daylight now. 

    Maths with Orion, every Friday at 11:00am GMT

    Orion has classes. I'm only at home today because I woke up wanting to throw up.

    Yep, and now you have a class with all of us.

  • ModernFable
    ModernFable Member Posts: 836
    Thank you so much.
  • Dwight_Confusion
    Dwight_Confusion Member Posts: 1,650

    @McLean

    I'd love it, if you could weigh in on the cosmetic debate... please?

  • ModernFable
    ModernFable Member Posts: 836
    So how do you calculate it when it’s multiple effects applying? Such as Sloppy Butcher and Dying Light.
  • Khalednazari
    Khalednazari Member Posts: 1,433
    So how do you calculate it when it’s multiple effects applying? Such as Sloppy Butcher and Dying Light.
    @Orion answered it in this thread. https://forum.deadbydaylight.com/en/discussion/26150/math-question#latest
  • ModernFable
    ModernFable Member Posts: 836
    So how do you calculate it when it’s multiple effects applying? Such as Sloppy Butcher and Dying Light.
    @Orion answered it in this thread. https://forum.deadbydaylight.com/en/discussion/26150/math-question#latest
    Okay, that’s what I thought.
  • Khalednazari
    Khalednazari Member Posts: 1,433
    McLean said:

    Orion is right about how the multiple negative effects stack. The secret in the sauce is that positive action speed modifiers are added together before being applied, whereas negative action speed modifiers are applied sequentially. Let's say you have Botany Knowledge (+33%) and Resilience (+9%), but you're Mangled (-20%) and using Self Care (-50%). Charges per second will be (1+0.33+0.9)*(1-0.2)*(1-0.5) = 0.568. Healing takes 16 charges, so it'll take 16 / 0.568 = 28.16 seconds to heal.

    I think this comes across as confusing for most because they expect the percentages to be based on time, rather than speed. Descriptions could be a little clearer on that.

    Thank you. Yeah, would love some changes in the descriptions to clear this confusion for players who do not understand how it works. 
  • Orion
    Orion Member Posts: 21,675
    edited October 2018

    A dev commented in my thread - twice. I can die happy.

    Yes, I'm a dev fanboy. Sue me.

  • Kind_Lemon
    Kind_Lemon Member Posts: 2,559
    McLean said:

    Orion is right about how the multiple negative effects stack. The secret in the sauce is that positive action speed modifiers are added together before being applied, whereas negative action speed modifiers are applied sequentially. Let's say you have Botany Knowledge (+33%) and Resilience (+9%), but you're Mangled (-20%) and using Self Care (-50%). Charges per second will be (1+0.33+0.9)*(1-0.2)*(1-0.5) = 0.568. Healing takes 16 charges, so it'll take 16 / 0.568 = 28.16 seconds to heal.

    I think this comes across as confusing for most because they expect the percentages to be based on time, rather than speed. Descriptions could be a little clearer on that.

    You wrote Resilience as .9 in you’re  calculations instead of .09 fyi. You still used .09 when calculating, however.

    Why are positive modifiers not applied the same way as negative ones? (I understand that if negative modifiers were done like the positive ones, you could end up with a 0 charge per second result.)
  • Orion
    Orion Member Posts: 21,675

    @Kind_Lemon said:
    Why are positive modifiers not applied the same way as negative ones? (I understand that if negative modifiers were done like the positive ones, you could end up with a 0 charge per second result.)

    It's probably because it's more intuitive to do it like that. That would be my guess.

  • Orion
    Orion Member Posts: 21,675

    Seems some people still didn't get the message.

  • Khalednazari
    Khalednazari Member Posts: 1,433
    Orion said:

    Seems some people still didn't get the message.

    Lol
  • RepliCant
    RepliCant Member Posts: 1,436
    edited November 2018

    Let me know if this isn't the place to ask but,

    What happens when you have two negative speed modifiers that do not stack? i.e Sloppy Butcher & Thanatophobia. Which one would be applied first? And why?

    Also, could you put the equation for speed modification in an unknown form? (Algebra, I have an extremely hard time deciphering equations like this when the numbers are already inputted. Me dumb.) If not that's totally cool, I'd do it myself but my head is getting confused with all these numbers

  • Orion
    Orion Member Posts: 21,675
    edited November 2018

    @Brady said:
    Let me know if this isn't the place to ask but,

    What happens when you have two negative speed modifiers that do not stack? i.e Sloppy Butcher & Thanatophobia. Which one would be applied first? And why?

    Also, could you put the equation for speed modification in an unknown form? (Algebra, I have an extremely hard time deciphering equations like this when the numbers are already inputted. Me dumb.) If not that's totally cool, I'd do it myself but my head is getting confused with all these numbers

    I assume the strongest debuff would be applied, whatever that may be. However, that's a programming question, and my answer is based on how I would do it.

    The speed decrease is simply Π(1-xi), i = 1, ... , k; where x is the speed decrease, i is the index (in case there are many debuffs; each xi corresponds to a different debuff), and k is the total number of debuffs. The time increase is 1/Π(1-xi), i = 1, ... ,k. If you're not familiar with this notation, see here: https://en.wikipedia.org/wiki/Multiplication#Capital_Pi_notation

    Post edited by Orion on
  • Bravo0413
    Bravo0413 Member Posts: 3,647

    Bump!

  • Tru3Lemon
    Tru3Lemon Member Posts: 1,358

    @Orion wheres youre damm oscar of the year xd

  • ABannedCat
    ABannedCat Member Posts: 2,529

    My guess would be that its to prevent negative modifiers from exceeding -100%

    For example Self Care -50%, Coulophobia is another -50%. If those 2 were added together before being applied, you would end up with not being able to heal at all.

  • Peanits
    Peanits Dev Posts: 7,555

    This is true. Throw sloppy butcher into the mix and you would actually be hurting yourself at 20% speed if that were the case.

  • AntiJelly
    AntiJelly Member Posts: 1,155

    How does charge efficiency work then? Like, for example, what's happening when you run an Emergency Med-Kit (the green one) with Botany Knowledge?

    Are there separate numbers for item charges and charge contributions?

    Because with Emergency Med-Kit and Botany, you're contributing 1.83 c/s, but then would that mean that you're only using 1.17 c/s out of the Med-Kit?