Blizzard Defends Skill Point Removal

Posted 3 August 2011 by Flux

A fan referenced the “97 billion possible character builds” quote from Blizzcon 2010, and asked how the math had changed now that the max skills at one time per char is 6, instead of 7. Bashiok had clearly consulted with his superiors on that issue, and had a FAQ-style post, with a bonus confusing mathematical metaphor, all ready to go.

He explains their logic behind the skill point removal, talks about encouraging character variety, and calculates the possible number of char builds under the new six-skill maximum. This is probably the single longest post Bashiok has ever made, so here’s just the start quoted; click through for the whole thing, and another subsequent thread on basically the same issue of character variety in D3.

97 billion builds per class @ Blizzcon. So, whats the new number of the titanic amount of customization?
Bashiok: I realize there’s a lot of information spread around, I’m hoping to bring some of it to a single post and hopefully get our point across and reassure you that the changes we’re making are for the betterment of character customization options, and ultimately your long-term enjoyment of the game.

So, why did we get rid of skill points?
(Note: this is a supplementary min/max explanation. There are lots of other reasons which have been touched on in the past such as how players approach our game, supporting the idea of builds, observing how players behaved in internal testing, etc. This is just further explanation that I think will resonate with some of you.)

In Diablo III, we really want to improve the combat depth. Part of having combat depth involves having skills that are useful in different situations. In Diablo II players often used a single skill to deal with almost all situations: Blessed Hammer, Frozen Orb and Bone Spirit to name a few. Players invest 20 points into a single skill and use it as much as possible. The only reason a player would swap away from their primary spam skill is due to monster resistances/immunities. If a monster was immune to your primary spam skill, you’d either skip the encounter completely or fall back on a second skill. Neither of these answers provides the player with much combat depth.

Bashiok’s post continued….

To support combat depth, skills need to have different roles. Here is a very simple example:

  • Magic Missile deals 15 damage to a single enemy
  • Arcane Orb deals area of effect damage for 10 damage each

With these two skills we’re beginning to develop some combat depth for the player. Use Magic Missile when you’re facing one enemy, use Arcane Orb when you’re facing multiple enemies. But you may also want to use Magic Missile if one enemy is a “high priority target” in a group, and you want it to die quickly. In this simplified example players can still defeat a horde of enemies by casting Magic Missile multiple times, or they could defeat a single large enemy by casting Arcane Orb multiple times, but that wouldn’t be as efficient as a player who uses the right skill for the right situation.

Ok so that basic layout of combat depth out of the way!

With skill point spending your skills get better as you invest points into them. The problem is that this destroys combat depth. If after pumping a bunch of points into Magic Missile it now deals 70 damage to a single enemy, assuming my enemies have any reasonable health, then Magic Missile becomes a better choice than Arcane Orb even in group situations. If after pumping a bunch of points into Arcane Orb it now deals 45 damage, then it deals more damage than Magic Missile to single targets. Now rather than using the right skill for the right situation, I’m using the skill I’ve put all my points into. Skill point spending has eroded away combat depth.

Why did we go from 7 skill choices to 6?
(Note: again, this is a supplementary explanation. We’ve gone over some of the other reasons elsewhere, but this is specifically targeted at those of you here who feel strongly that 7 means there would be more build diversity than 6)

Diablo III emphasizes build customization. We feel that 6 skill choices actually creates more build diversity than 7.

Why? Well for any given set of options, the greatest number of combinations exists when the number of choices you can make is close to half the number of options you have. Some of you may remember a high school math problem like this: There are 12 differently colored marbles in a bag. How many different color combinations can you get by choosing X marbles? Well as it turns out the solution for various values of X are:

  • 1 marble: 12 different color combinations
  • 2 marbles: 66
  • 3 marbles: 220
  • 4 marbles: 495
  • 5 marbles: 792
  • 6 marbles: 924
  • 7 marbles: 792
  • 8 marbles: 495
  • 9 marbles: 220
  • 10 marbles: 66
  • 11 marbles: 12
  • 12 marbles: 1 (there’s only 1 way to choose 12 marbles from the 12 in the bag)

The greatest number of possible combinations happens when you are choosing 6 from a possible 12.

You may be asking what 12 has to do with anything as classes all have over 20 skills available to them…

This is true in theory, but in practice players tend to (and really should) pick up skills to fill different roles so they can be effective. Categories such as single target, area of effect, auto-targeting, debuff, defensive, group buff, escape, crowd control, 2-minute ubers, pet skills, etc. etc. Players generally take at most two (and often one) skill to fill any particular role. For example, the Wizard has Ice Armor, Storm Armor and Energy Armor, but I don’t think anyone is going to take all three (though maybe somebody will take that as a challenge and prove me wrong), most players will choose one Wizard Armor spell (note that this can change dramatically with some rune effects). If we look at each class, depending on how you count, you get anywhere from 8-12 different types of skills. So we err on the high side in our category estimate (12) and that means 6 is a pretty good number to maximize build variety.

It’s important to note that we’re not just talking about you and your friend having Wizards with slightly different skills, we’re talking about you and your friend having 6 skills that are different in functionally significant ways.

Closing remark! When we pull math out like this I’m sure somebody will point out that if our only objective was to maximize build combinations we’d have allowed people to also choose 6, 7 or 8 passives rather than just 3. So I’ll counter by saying maximizing build combinations is not our only objective. We also want our system to have aesthetic flavor, to be simple to understand, and to have the passives in particular feel impactful. We have many different goals that we take into account when making any design decision. In the case of active skills, we felt the increase in variety was one of many good reasons to go from 7 to 6.

So how many skill combinations are there now?

Well taking into account 6 active skills, all the rune combinations, and 3 passives we currently expect each class to have roughly 2,285,814,795,264 different build combinations. That’s not taking into account skill types for ‘ideal’ builds, but that’s always been a big part of the fun of experimenting (and longevity for Diablo II) – finding a build that shouldn’t work, and making it.

  • Can this be dumbed down for me? I’m terrible at math.

    How do they come up with such an absurb build number? How can it possibly be that high?

    How many skills and runes are there? Does that determine the number?

    • So, the number basically represents the number of different skill types. Here Bashiok is saying that it’s roughly 12 or so.
       
      Basically, half of any number allows for the most combinations. IE: because you are more restricted, there is more you’re leaving out. So, in effect, there’s more noticible and significant build diversity.

    • To be clear, I did not do this math, or make this original post:

      1,514,205,000,000 different Skill/Rune combinations per character.
      720 Passive Skill combinations.
      1,090,227,600,000,000 different builds per character.
      5,451,138,000,000,000 different builds in the game.

      Where’s the customization Blizz? You’re ruining the game!!1!ONE!

      These calculations are based on the following:

      24 Skills per character
      6 Skills are actually chosen
      All Skills are runed
      Only 10 Passive Skills per character

      [(24*5)*(23*5)*(22*5)*(21*5)*(20*5)*(19*5)]*(10*9*8)*5

      • You should divide these by (720*6) = 4320.  Since you only care about which skills are picked, not which order (it doesn’t matter which skill is in which slot).  This should get you closer to Blizz’s number, but they might have 15 passives, I think I read somewhere?  Too much new information…

  • More builds than stars in the Universe!
    Cool

    Wait, there is only one build if WE CAN CHANGE OUR SKILLS FOR FREE, right?

    • Actually there are five builds, because there are five characters.

    • That is if you can farm enough to constantly switch out 7 tier runes.
      Same holds true for any game you can respec?

      From Jay Wilson interview: Jay Wilson imply that your rune with disappear when you respec unless you remove it first by paying the mystic. He also said that Tier one rune is popular therefore in early you can test things out and you need to start to settle on one build in late game unless you farm a lot.

    • Um I dont know if you were being literal or not but there are a hell of a lot more stars in the universe than even those numbers. Try about 10^23 or so as an estimate.

  • I still don’t really feel that “builds” exist because you can swap skills in and out at-will.

    • They are thinking about making it so that in Nightmare and Hell modes you are unable to change your skills out unless you are in town. So unless someone wants to waste time by going back and forth back and forth they wouldn’t be able to change skills in and out at-will.

  • You could change your build like that in guildwars.. its still called a build. (yes diablo isnt guildwars I know), The main thing that will stop people from changing builds all the time is that rank 7 runes will be really rare, and for your final build u will want all your skills to have rank 7 runes. So yea u could switch out a skill for another, but until you have 24 rank 7 runes, (and thats implying you don’t care which rune effect you get) you won’t want to switch a skill, because it will be weak.

  • There is no way it could possibly have more builds than if you could independently select where each skill goes, before each skill had 1-5 possible combinations and now it has 1.  Also his marble example makes no sense, there is not 12 skills to choose from, its just another cop out answer.

  • With regards to changing skills instantly I don’t see this as an issue as this was pretty much available in D2 anyways with the reroll. Only difference is that it is free. I feel like for a ‘build’ you generally have gear and combinations that are optimal to deal with certain situations – all this does is prevent you from going through boring skill spamming (Blizzard/Hammers) because now you have more USEFUL skills. I mean if your intent was to play the game as it is meant to be played you would simply change skills when you wanted to change the flavour of your character. 

    I like it because this means that instead of having a 3 barbs, I can have 1 WD 1 Barb and 1 DH. Not all of us having 100000s of hours to put towards leveling characters (which we did through pointless rushing/xp runs)

  • They math is very long if done on paper, but they did not do it that way. Anyone can do if you have a graphing calculator TI-83 or better. I’ll tell you guys its really easy. I learned it in Calculus class last semester. They make it sound like they have smart mathematicians come up with that number. Then post it on a powerpoint to impress everyone at Blizzcon last year. All they did ishave one guy punch it in the calculator and it does all the work for you. If you have graphing calculator and want to see for your self Ill tell you how to do it.  Press the MATH button below the alpha button Arrow key over to PRB Then you should see list, Look at number 2 and 3. 2 says nPr and 3 says nCr The difference between the two is nPr is when order matters and nCr is when order does not matter. n means number of choices and r means number picked. All you do is go back to a blank screen. Push in any number, in this case will enter in 25. I cant remember the total number of skills if its 20 or 25? So if 25 is wrong follow the same steps and just enter in the correct number.   Then push the MATH button. Scroll over to  PRB. Select nCr becasue order does not matter. Hit enter You should see 25 nCr Then just enter 6. Which is the the total number of skills we can have active. It should look like 25 nCr 6. Hit enter and there is your total number of combanations 1,177,100. See how easy that was? Keep in mind though. This is just for the 25 active spells combinations. Not the passive ones. Follow the same steps and you can find that number. Then you take that passive number combinations and active skills combinations number add them together. The add 6 active+3 passive =9. So 9 is your r and the two passive and active combinations added together is your n. Follow the steps and you will have that crazy number he through up. He could have made it up also?  You can check his math by doing these steps if you knew the actual number of skills and passives you have now.  Still dont believe me? Do that marble example he did with the steps 12 nCr 6 = 924  Change the to all the other numbers 1,2,3,4 etc. You will get them same answers. Im horrible at math and I know how many builds you can have Blizzard. Your not as smart as you think you are :)  

    • lol… Any student that finish high school should able to do this. This is grade 12 math in Canada. It is just basic combinatorics. It is not even combinatorics with identical object which is a little harder than this.

  • At first I didn’t like the reduction in skill slots, but after learning that we can change skills freely with no penalty, I’m becoming much more accepting of the changes.
    AH is seeming much more acceptable now, too.  BUT HEALTH GLOBES MUST DIE! :choler:

  • I think it’s great that they put so much effort into build customization. When the game is no longer Diablo II, everyone panics a little bit. I mean, I smile when I hear the bow sound in the game demos, because it reminds me of both Diablo 1 and 2. But all the speculation, and excitement and explanation a theory seems really, really stupid. Just release the damn game and get on with it. Who the hell writes a 2 page memo on the mathematics involved in character building in a game that hasn’t even been released yet? This is kind of insane.

    • “Who the hell writes a 2 page memo on the mathematics involved in character building in a game that hasn’t even been released yet? This is kind of insane.”
       
      No.
       
      THIS. IS. DIABLO 3!!!!!!

  • Also he could be counting the Runes changes as well? Whoknows really? Its freaking really high that’s the point they are trying to make.

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