Game Mechanics: Memory Blur Calculation

[Daldaen]

From my experience playing an enchanter on P99, I feel our Memory Blur calculation is incorrect. It favors a success roll too much here I believe.

Memory Blur success chance should be a sum of three values:

1. Level of Mob Factor
2. Spell Raw Value
3. Charisma Factor

Level Based Factor:

The way Devs described the first factor, is like this:

Mobs below level 17, have a 100% value to memory blur
Mobs above level 53, have a 25% value to memory blur

They are less clear on what happens to mobs inbetween that range, but I believe we can safely assume a linear model, in which case it can be represented by this function:

Level Based Chance = -2.08333 * Level + 135.4167

Spell Raw Value:

This is simply the value shown in the spell data for the actual memory blur component. For example, Blanket of Confusion has a built in 20% Memory Blur Raw Value (however it should be noted Blanket has 2 of these, meaning it should perform the memory blur roll twice, making it the most reliable memory blur available to Enchanters)

Charisma Factor:

This is simply (CHA - 150) / 10. Meaning a max (255) CHA enchanter would have a 10.5% value.

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

Example 1: let's use any ToV trash mob (excluding baby drakes), with an enchanter using Memory Flux, with 255 CHA.

1. Level Component for level 53+ mob = 25%
2. Raw Value for Memory Flux = 30%
3. Charisma Calculation for 255 CHA = (255-150)/10 = 10.5%

Sum = 25+30+10.5 = 65.5% Chance your Memory Flux spell should roll a success and blur the target.

Example 2: let's use any ToV trash mob (excluding baby drakes), with an enchanter using Blanket of Confusion, again with 255 CHA.

1. Level Component for level 53+ mob = 25%
2. Raw Value for Blanket of Confusion = 20%
3. Charisma Calculation for 255 CHA = (255-150)/10 = 10.5%

Sum = 25+20+10.5 = 55.5% Chance your Blanket of Confusion spell should roll a success.

HOWEVER! This check is performed twice. So the chance that either both rolls are a success or atleast one roll is a success is most easily calculated by:

1-(1-.555)^2 = 80.2% Chance that you Successfully memblur (basically check the chance of failing both rolls and see the difference from 100%)

Example 3: let's use a max level Illis Froglok in Sebilis, when using level 4 Mesmerize, and again 255 CHA.

1. Level Component for level 53+ mob = 25%
2. Raw Value for Memory Flux = 1%
3. Charisma Calculation for 255 CHA = (255-150)/10 = 10.5%

Sum = 25+1+10.5 = 36.5% Chance your Level 4 (or any mez due to them all having a 1% memblur) should roll a success and blur a target.

Evidence:

Naturally for something this specific you need developer quotes, and of course those aren't in era but something this inherent in the game code is unlikely to have been modified hugely over the games life:

http://www.eqclerics.org/forums/showthread.php?t=23401

Base effect 1 is a % bonus for the effect to occur.
The player is given a percentage bonus based on level, lower is better. < 17, bonus = 100, > 53 bonus = 25.
Another bonus is applied for charisma. (Cha - 150) / 10 up to a maximum of 15.
So if you have 150 charisma or higher, the initial 1% mem blur become: 1 + 15 + 25 = 41%

Discuss.