Calculating Parry Chance in Cataclysm

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Re: Calculating Parry Chance in Cataclysm

Postby Koatanga » Fri Apr 30, 2010 1:25 pm

Raivnor wrote:It does seem to indicate, however, that Parry will become cheaper than Dodge per point, or at the very least similar. This makes sense when you consider this Block 2.0. It is a little out of the purview of this forum, but as an aside DKs already have a block like mechanic in Blade Barrier and it wouldn't surprise me if they tuned that to be a little more in line with block, rather than have DKs with enough parry to compensate for their lack of block.

The difference is that we can get additional block % from gear, while DKs can't get additional blade barrier that way. They can, however, get more parry. Parry gives them a mitigation stat they can stack, giving them the choice of gemming parry for mitigation or dodge for avoidance.

I know they want to simplify gear, but I would still expect them to offer different variations for tanks (avoidance vs mitigation), and I imagine different fights will slightly favour different stats.

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Re: Calculating Parry Chance in Cataclysm

Postby Marblehead » Fri Apr 30, 2010 1:28 pm

Disclaimer: Long post ahead. Proceed with caution! The following post doesn't intend to prove someone wrong. It's just a written expression of thoughts.

theckhd wrote:Well, it's not really a separate attack table. The attack table is generated dynamically - if you gain 100 defense rating from a proc, your avoidance chances go up immediately and stay that way until the buff drops off. Everything in this thread would work the same way in that context, in that after a parry you'd have a "buff" that pushed block and hit off the table (i.e. +100% parry). That buff could be visible or invisible depending on how they coded it, though visible makes the most sense to me.

The GC quote does indicate that their design model at that point had the "parrywall" buff become active after a parry, but had it being consumed on the next attack table roll regardless of outcome. However, it's a glimpse of the mechanic very early in the design process, and it wouldn't surprise me if they found that it was more convenient or consistent to make the buff carry over than to reduce the itemization cost of parry to compensate for missed opportunities.

Obviously, it's to early to tell how parry will work. My point is that there are other scenarios too, which are equally possible to happen.

I'll use 3 boolean variables to assemble the possible scenarios.

1) chain = Parry reduction can chain
2) stack = Parry reduction can stack with itself or Block
3) table = Parry pushes Block and Hit off of the attack table

Assumptions: a) GC comment is valid, b) Block damage reduction is 30% (just for the numbers)


Scenario 1: chain = FALSE , stack = FALSE , table = FALSE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be anything (table = FALSE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 50% (stack = FALSE). Parry buff is consumed (chain = FALSE).
If the 2nd attack is a Block, then damage reduction is 50% (stack = FALSE). Parry buff is consumed.
If the 2nd attack is a Hit, then damage reduction is 50%. Parry buff is consumed.

In any case, 3rd attack is exactly like the 1st attack.


Scenario 2: chain = TRUE , stack = FALSE , table = FALSE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be anything (table = FALSE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 50% (stack = FALSE). Parry buff is refreshed (chain = TRUE).
If the 2nd attack is a Block, then damage reduction is 50% (stack = FALSE). Parry buff is consumed.
If the 2nd attack is a Hit, then damage reduction is 50%. Parry buff is consumed.

In case of a Parry, 3rd attack is exactly like the 2nd attack, else it's exactly like the 1st attack.


Scenario 3: chain = FALSE , stack = TRUE , table = FALSE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be anything (table = FALSE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 75% (stack = TRUE). Parry buff is consumed (chain = FALSE).
If the 2nd attack is a Block, then damage reduction is 65% (stack = TRUE). Parry buff is consumed.
If the 2nd attack is a Hit, then damage reduction is 50%. Parry buff is consumed.

In any case, 3rd attack is exactly like the 1st attack.


Scenario 4: chain = FALSE , stack = FALSE , table = TRUE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be Miss, Dodge or Parry (table = TRUE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 50% (stack = FALSE). Parry buff is consumed (chain = FALSE).

In any case, 3rd attack is exactly like the 1st attack.


Scenario 5: chain = TRUE , stack = TRUE , table = FALSE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be anything (table = FALSE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 75% (stack = TRUE). Parry buff is refreshed (chain = TRUE).
If the 2nd attack is a Block, then damage reduction is 65% (stack = TRUE). Parry buff is consumed.
If the 2nd attack is a Hit, then damage reduction is 50%. Parry buff is consumed.

In case of a Parry, 3rd attack is exactly like the 2nd attack, else it's exactly like the 1st attack.


Scenario 6: chain = TRUE , stack = FALSE , table = TRUE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be Miss, Dodge or Parry (table = TRUE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 50% (stack = FALSE). Parry buff is refreshed (chain = TRUE).

In case of a Parry, 3rd attack is exactly like the 2nd attack, else it's exactly like the 1st attack.


Scenario 7: chain = FALSE , stack = TRUE , table = TRUE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be Miss, Dodge or Parry (table = TRUE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 75% (stack = TRUE). Parry buff is consumed (chain = FALSE).

In any case, 3rd attack is exactly like the 1st attack.


Scenario 8: chain = TRUE , stack = TRUE , table = TRUE

The 1st attack is a Parry and results in 50% damage reduction. The 2nd attack can be Miss, Dodge or Parry (table = TRUE).

If the 2nd attack is a Miss, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Dodge, then damage reduction is 100%. Parry buff is consumed.
If the 2nd attack is a Parry, then damage reduction is 75% (stack = TRUE). Parry buff is refreshed (chain = TRUE).

In case of a Parry, 3rd attack is exactly like the 2nd attack, else it's exactly like the 1st attack.

-------------------------------------------------------------------------------------

Personal opinions:

i) (chain = TRUE and table = TRUE) is highly unlikely to happen, cause having 0% Miss chance and 0% Dodge chance would only require one Parry to enter a state of constant reduced damage. This would discourage tanks from gearing Dodge, so I strongly believe that scenarios 6 and 8 are out of the question.

ii) (chain = FALSE and stack = TRUE) is also unlikely to happen. I find it illogical for a 2nd Parry to further reduce the incoming damage (meaning it's a new parry) and not carry on to the next attack. Because of that, I would also exclude scenarios 3 and 7 from the list of possible scenarios.

iii) Scenario 1 is essentially the same with scenario 4, while scenario 2 is the same with scenario 6. Since it doesn't make sense for Parry, Block and Hit to provide exactly the same damage reduction, I would say that scenarios 1 and 2 our out too.

iv) The remaining scenarios are 4 and 5. This thread is about scenario 4. However, at this point of time, I think that both scenarios have 50/50 chances of going live. The only thing that could change that is if Blizz decide to GC's comment invalid.
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Re: Calculating Parry Chance in Cataclysm

Postby Koatanga » Fri Apr 30, 2010 5:23 pm

I disagree that Scenario 2 is invalid, and in fact I have my money on Scenario 2 as the option they will choose.

Without the rest of the attack table, you lose the possibility of a critical block following a parry. This would be detrimental for someone with high levels of block crit.

I think they will do an attack table roll to determine if the attack is successful or not, and if it is they will apply the largest damage reduction possible between miss, dodge, parry, or block. Thus if the following attack is blocked for 30%, the parry charge would replace the block reduction (50% > 30%) and the attack would be 50% reduced. If it is a critical block, the block would override the parry charge (60% > 50%) so the attack would be 60% reduced.

In all cases, the original parry charge is consumed. However, if the 2nd attack is also parried then a new charge from that parry would apply to the 3rd attack.

That scenario makes the most sense to me as it accounts for block crit %, whereas people with higher block crit chance (aka Warriors, from mastery) would be penalised if the full attack table was not considered.

The "parry refresh" never triggers a chain of damage reduction because the parry charge gained from the first attack is always consumed by the 2nd attack. In the case of consecutive parries, it may appear that the charge got forwarded to the 3rd hit, but in fact it is a new charge form the second parry. The 4th attack would be just like the 1st again unless the 3rd was also a parry (a wonderful run of luck). But for any n consecutive parries, n+1 attacks would be reduced by at least 50%, not n + n.
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Re: Calculating Parry Chance in Cataclysm

Postby theckhd » Fri Apr 30, 2010 5:39 pm

I agree that chain and table will not simultaneously be true, for exactly the reason you gave. There's another scenario you missed, which is the one I proposed - parry buff not being consumed on miss/dodge. I don't think it's all that unlikely, as it's one obvious way to prevent miss and dodge from conflicting with parry.

The reason I don't think it's that unlikely is that the other way to handle the conflict is to reduce the itemization cost of parry (because you "lose" some of it). If they do that, they have to be careful, because they could get into a situation where parry rating is so cheap that you can stack it and break the system. If you're already into a region of harsh DR after the first raid tier, things will be ugly.
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Re: Calculating Parry Chance in Cataclysm

Postby Slept » Fri Apr 30, 2010 6:36 pm

Miss and dodge eating parries is a relatively minor issue. Dealing with block consistently is the bigger problem, I think.
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Re: Calculating Parry Chance in Cataclysm

Postby Marblehead » Sat May 01, 2010 6:40 am

@Koatanga

I admit that it was my mistake to equate scenario 2 with scenario 6, since the chain factor makes them quite different. Of course, scenario 2 will not suffer from the constant parry chains like scenario 6. But there is another reason that makes scenario 2 non-viable.

Let's say that a boss attacks the player and the game rolls on the attack table for the result.

If it rolls for a miss or a dodge, then it's 100% damage reduction.
If it rolls for a hit, then it checks if the player has the parry buff and applies 0% (if the buff isn't up) or 50% (if the buff is up) damage reduction.
If it rolls for a block, then it rolls again for the crit. Afterwards, it checks if the player has the parry buff and applies the higher damage reduction.
If it rolls for a parry, then it applies the parry buff, overwriting the previous if it exists. The hit is reduced by 50% and consumes the one charge of this new parry buff, leaving one for the next attack.

The thing that makes me doubt this scenario is that after a parry, the next attack will be reduced the same in case of a hit or a new parry. If 2 consecutive parries occur, the player loses completely a parry charge. That would make players to benefit more from a parry followed by a hit than followed by a parry. It just doesn't make sense to me to pray for the next attack after a parry to not be a new parry just so you can benefit from the 2nd charge of the 1st parry. That's why (stack = FALSE and chain = TRUE) doesn't seem likely to me.


@Theckhd

I didn't missed that scenario and I agree that it's viable. I just chose to take GC's post (parry buff is consumed by a miss/dodge) as a given. Of course, there is always the possibility for that to be changed in beta, but since it's the only official information at this time, I decided to stick with it.
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Re: Calculating Parry Chance in Cataclysm

Postby Koatanga » Sat May 01, 2010 4:44 pm

Marblehead wrote:The thing that makes me doubt this scenario is that after a parry, the next attack will be reduced the same in case of a hit or a new parry. If 2 consecutive parries occur, the player loses completely a parry charge. That would make players to benefit more from a parry followed by a hit than followed by a parry. It just doesn't make sense to me to pray for the next attack after a parry to not be a new parry just so you can benefit from the 2nd charge of the 1st parry. That's why (stack = FALSE and chain = TRUE) doesn't seem likely to me.

The difference between a parry followed by a hit and a parry followed by a parry is that the 2nd parry would give a new parry charge to use on the 3rd hit, while the hit would not. The player would still benefit more form the parry unless it was the final blow of the fight.

As for losing a parry charge, I am betting that will be the case. I think it would be silly for them to accrue a series of parries that get used if no equal or better DR applies. By the end of a boss fight you'd have 20 or 30 parry charges queued up that you would never use anyway, so you might as well just overwrite the active one.

Maths isn't my forte, but it seems to me that once you get past 50% dodge+miss+parry, you start to overwrite more parry charges than you actually use.
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Re: Calculating Parry Chance in Cataclysm

Postby Awyndel » Sat May 01, 2010 5:49 pm

Cmon guys save your energy for the beta testing. Enough guessing already, we have plenty to work with :) .
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Re: Calculating Parry Chance in Cataclysm

Postby Marblehead » Sat May 01, 2010 5:56 pm

Koatanga wrote:
Marblehead wrote:The thing that makes me doubt this scenario is that after a parry, the next attack will be reduced the same in case of a hit or a new parry. If 2 consecutive parries occur, the player loses completely a parry charge. That would make players to benefit more from a parry followed by a hit than followed by a parry. It just doesn't make sense to me to pray for the next attack after a parry to not be a new parry just so you can benefit from the 2nd charge of the 1st parry. That's why (stack = FALSE and chain = TRUE) doesn't seem likely to me.

The difference between a parry followed by a hit and a parry followed by a parry is that the 2nd parry would give a new parry charge to use on the 3rd hit, while the hit would not. The player would still benefit more form the parry unless it was the final blow of the fight.

As for losing a parry charge, I am betting that will be the case. I think it would be silly for them to accrue a series of parries that get used if no equal or better DR applies. By the end of a boss fight you'd have 20 or 30 parry charges queued up that you would never use anyway, so you might as well just overwrite the active one.

Maths isn't my forte, but it seems to me that once you get past 50% dodge+miss+parry, you start to overwrite more parry charges than you actually use.

Actually, I don't mind losing a parry charge, but in exchange of what?

If I dodge or miss, I exchange it for 100% damage reduction. I'm fine with that.
If I crit block, I exchange it for 60% damage reduction. That's fine too.
If I block or get hit, I exchange it for 50% damage reduction. That's what parry is supposed to do anyway.
If I parry, I exchange it for another charge? Well, it could be, but I wouldn't be happy about that.

Let's say that a boss hits for 20k damage. Also, let's assume a sequence of 6 hits that consists of 3 hits and 3 parries.
If the sequence is parry-parry-parry-hit-hit-hit then the incoming damage is 10k+10k+10k+10k+20k+20k=80k
If the sequence is parry-hit-parry-hit-parry-hit then the incoming damage is 10k+10k+10k+10k+10k+10k=60k

And here comes my question? Why a sequence of the same number of dodges, parries, misses, blocks and hits should result in a different amount of incoming damage depending on the consecutive parries? Why should I pray to the mighty god of rolls to grant me as less consecutive parries as possible in every fight? It could happen, but I won't be happy for having another form of sheer randomness.
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Re: Calculating Parry Chance in Cataclysm

Postby Koatanga » Sat May 01, 2010 6:44 pm

I see that as a down-side to it as well, but I will be surprised if they let it stack or accrue. I think it will just be the down-side of parry, and give the maths-people something to sim.

Again the reason I believe they are making the change is to make tank plate more universal. Block chance can be confined to pally/warrior tier, guns/librams, and shields, leaving shared drops free to focus on dodge and parry that all plate tanks would want. On DK tier, they can give lots of parry without making DKs unbalanced in terms of avoidance.

All plate tanks would be similar in avoidance, because avoidance would be just dodge + miss. Mitigation from parry/block could be balanced so that whether they block, critical block, or parry, all plate tanks of equal gear level also mitigate about the same over the course of a fight.

If all parry charges got used in one way or another, it would make parry the more desirable tanking stat and give DKs an edge that would scale not scale the same as block. The more you parry, the greater the influence of saved parry charges.

Generic plate tank gear and an easy-to-balance model that would scale equally while still providing flavour would seem like a good way to go. For that reason, I believe it is the path Bliz will follow.
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Re: Calculating Parry Chance in Cataclysm

Postby tlitp » Fri Jul 02, 2010 12:28 am

@ Theck : do you feel lucky, punk ? :P

It seems that there is no need to reinvent the wheel. The PHR module will likely stay where it is, although an iterative model is rather superfluous at this point.
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Re: Calculating Parry Chance in Cataclysm

Postby theckhd » Fri Jul 02, 2010 8:39 am

tlitp wrote:@ Theck : do you feel lucky, punk ? :P

It seems that there is no need to reinvent the wheel. The PHR module will likely stay where it is, although an iterative model is rather superfluous at this point.

Yup, I mentioned exactly the same thing in one thread in the Cataclysm forum. As long as we retain parry-haste but mobs do not, the iteration is unnecessary and the math becomes a lot simpler.

We really wouldn't need a separate PHR module at that point, since it should be a one-line calculation. You just have an extra term/factor to represent additional haste afforded by parries.
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Re: Calculating Parry Chance in Cataclysm

Postby ArgentSun » Sat Jul 03, 2010 8:35 am

Skimming over the replies, I didn't see anybody mention that parry is likely to go back to its current version. Here is the quote:
We're also not happy with the new implementation of parry, where you take 50% damage from two swings. It sounded good on paper, but after testing it out we thought the second swing just feels goofy and confusing. Our plan is to revert parry back to 100% avoidance and remove the concept of swing speed increase for any creature (players could still do it). We would change the budget on parry to be exactly the same as dodge. We'd also like to add some more talent hooks that favor say parry over dodge for some classes -- stuff like "After a successful parry...."
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