Parry/riposte chance

[Reidar]

Does anyone know the formula for parry and riposte chance? I think I have read before that block for monks works about twice as often as parry, but not sure. Why are these things a secret and never explained anywhere?

[Naethyn]

Chapter 3: Preliminary Avoidance (Parry/Dodge/Riposte/Shield Block)

Preliminary Avoidance are checks that occur prior to a NPC actually landing a blow on you.

This is an explanation of how the defensive abilities fire in a nut shell.

The order is: Parry/Block --> Riposte --> Dodge --> Shield Block.

**Note: Nomenclature: Parry/Block will be refered to as "Parry" and Shield Block will be refered to as "Block". While no class gets both Parry and regular Block, tanks in particular use both Parry AND Shield Block thus, the guide will be written with that as the predominant theme.

Each defensive ability has a % chance of firing, thus causing you to avoid the attack. For the sake of easy math, lets assume each has a 10% chance to fire.

Mob attacks you:

First defensive tier: (Parry)
======================
Check 1: Parry (10%) So theres a 10% chance you successfully parry

Second defensive tier: (Riposte)
=======================

Parried?
(10% chance) Yes: Check 2: Still fires, Riposte (10%) but does nothing. Since you already "parried." Show "parried"

(90% chance) No: Check 2: Riposte (10%), attempt 2 at avoiding attack.

Not Parried, but Riposted: (9%...10% of the remaining 90%) Show "riposted"
-This shows that the chance to visibly see "riposted" is now 9%, regardless if parry fired or not

Third defensive tier: (Dodge)
=======================

Parried? (10% chance) Show "parried"

Not Parried: (90% chance)
---------------------------

Not Parried, but Riposted: (9%) Show "riposted"

Not Parried, AND not Riposted: (81% chance)
-------------------------------------------
Check Dodge (10%)

Not Parried, AND not Riposted, but Dodged: (8.1% chance..10% chance of the remaining 81%)

-This shows that the chance to visibly see "dodged" is only 8.1%

Fourth defensive tier: (Shield Block)
========================

Not Parried, AND, not Riposted, AND not Dodged: (72.9% chance)
----------------------------------------------------------------
Check Block (10%)

Not Parried, AND not Riposted, AND not Dodged, but Blocked: (7.29% chance):

-This shows that the chance to visibly see "blocked" is only 7.29%

In summation:
A single attack can be: dodged, parried, riposted and blocked, or any combination there of, but it will only "show" which ever checked first.

If you dodge and block a single attack, it will still show as "dodged" because you dodged it before you got to the shield block check point.

Since shield block is the last check, its ability decreases with every check before it. For you to see "You blocked suchandsuchs attack" It would mean you failed to dodge, parry, or riposte the attack first.

Mathematical summary:
=========================

Even though you started with:
10% chance to Parry
10% chance to Riposte
10% chance to Dodge
10% chance to Block

Does NOT mean only 60% of hits will get through!!!

In reality:

In this example, for every time a mob attacks you there is:
10 % chance you Parry it
9 % chance you Riposte it
8.1 % chance you Dodge it
7.29 % chance you Block it

and a 65.61% chance the mob hits you

So Block has a 10% chance to work, but an effective use of 7.29% because of earlier defensive checks. If you had Improved Dodge and Parry V, the *effective use* of block would drop even further

[Samoht]

^ Inclusion of block makes that obviously not within era.

[Jimjam]

Yes, but the percentages do seem to match up to those used in p1999.

However, monk block fires way more often than shield block does. If I remember my logs correctly, it might be close to 19% chance. Perhaps it is the first thing checked for monks?

Block may seem overpowered, but you must remember when eq was first released, itemisation was a large part of the balance. Monks did not get many high AC items, so relied on their skills and abilities instead of equipment to offset incoming damage.

By Velious they get the benefit of decent worn stats in addition to their excellent innate abilities, which left them with little drawback. This discrepancy between initial itemisation philosophy, game mechanics, and subsequent itemisation is what lead to the infamous 'monk nerf' at the start of PoP; at this point Sony realised the original game mechanics were not compatible with the direction they wanted to go with itemisation.

[fash]

For the sake of easy math, lets assume each has a 10% chance to fire.

OP was asking how to determine the actual value, which was just assumed to be 10% here. I think it's a function of skill level and level difference between attacker and defender. Are there other factors?

In pvp, both raw dex (of attacker) and agi (of defender) affect misses fwiw.

[7thGate]

So, there's a rather large caveat that this code is for stock eqemu, not p99. It is not clear if there have been changes to make it more classic, outside of obviously removing certain things like AAs, but if the code hasn't been modified it should work like this:

int chance = GetSkill(EQEmu::skills::SkillParry) + 100;
chance /= 45;
if (zone->random.Roll(chance)) {
hit.damage_done = DMG_PARRIED;
return true;
}

Omitted code for aa, spells, items, heroic dex, counter parry as nonclassic.
random.Roll rolls an integer 0->99 and checks that the result under the chance. This would mean that the chance to parry at 230 skill would be floor[(100+230)/45] = 7%

Eqemu uses 50 for Riposte, 45 for Parry and Dodge, and 25 for block as the divisors.
Capped, that should be 7% for Parry/Dodge, 13% for Block, 6% for Riposte. They stack multiplicatively, so the total chance an attack gets through a monk's active defenses would be 0.94*0.93*0.87 = 76%.

[ScruffMacBuff]

Does that 76% include the NPCs accuracy? Both enemies and players will just miss sometimes.

[7thGate]

No, that would just be the percentage of hits blocked regardless of the enemy's roll to hit or the defender's defense/agi/etc. Some additional percentage would be normal misses.

I did find an old dev post on monk vs. warrior vs. knight mitigation that the eq devs used as part of the analysis for the PoP monk nerf, and it looks like that had the parry/riposte/block/dodge chances about half of stock eqemu, so it could be closer to that.

[Jimjam]

Originally Posted by 7thGate [You must be logged in to view images. Log in or Register.]

I did find an old dev post on monk vs. warrior vs. knight mitigation that the eq devs used as part of the analysis for the PoP monk nerf, and it looks like that had the parry/riposte/block/dodge chances about half of stock eqemu, so it could be closer to that.

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