Tuesday, May 24, 2011

Pathfinder: % Chance to Hit Based on BAB

So I was working out mechanics for a character class and I came to an impasse when I was assigning it a BAB Progression. I wasn't sure, but it was POSSIBLE I had made a class that was able to be an effective melee combatant with Low* BAB Progression. I started to think... "Well then... I want to give it Medium* BAB Progression... but it might hit to often.... shit. What if I did low? No... I don't think it would EVER hit!"

*Low BAB Progression is that of a Wizard. (Ending in +10)
Medium BAB Progression is that of a Rogue. (Ending in +15)
Full BAB Progression is that of a Fighter. (Ending in +20)



So I set out to find the % chance to hit based on a character's BAB.
First I had to find AC to compare it to. I broke out my bestiary and averaged the AC at levels 1,5,10,15,and 20. It looks something like this:

Level Highest AC Avg AC Lowest AC
1 17 15 13
5 21 18 15
10 27 23 18
15 37 31 28
20 39 37 36

Then I jotted down the BAB progressions at levels 1,5,10,15, and 20.

Level Full BAB Med. BAB Low BAB
1 1 0 0
5 5 3 2
10 10 7 5
15 15 11 7
20 20 15 10


Encounters are balanced with SOME equipment and stats in mind so I decided to assign some bonuses (a LITTLE lowball.) at given levels based on my experience as a GM and Player.

Assuming
Total Bonus
1 +2 In Hit Stat 2
5
2
10 +3 In Hit Stat 3
15 +1 Weapon 4
20 +2 Weapon 5

That meant the following adjustments to my BAB Progression tables:

Level Full BAB Med. BAB Low BAB
1 3 2 2
5 7 5 4
10 13 10 8
15 19 15 11
20 25 20 15


So then I factored in dice rolls. I later used the Highest and Lowest Hits to calculate the percent chances to hit:



Full BAB
Level Highest Hit Avg Hit Lowest Hit
1 23 13 4
5 27 17 8
10 33 23 14
15 39 29 20
20 45 35 26



Med BAB
Level Highest Hit Avg Hit Lowest Hit
1 22 12 3
5 25 15 6
10 30 20 11
15 35 25 16
20 40 30 21



Low BAB
Level Highest Hit Avg Hit Lowest Hit
1 22 12 3
5 24 14 5
10 28 18 9
15 31 21 12
20 35 25 16

Though some math magic, I found the solutions.
(Basically the range of numbers that represented a successful hit over the total data range provided at a given BAB, represented as a percent)

This was the result:

Chance To Hit
Level Full BAB Med. BAB Low BAB
1 47.00% 42.00% 42.00%
5 52.00% 42.00% 36.00%
10 57.00% 42.00% 31.00%
15 47.00% 26.00% 5.00%
20 47.00% 21.00% --
Avg 50.00% 35.00% 23.00%

Notes:
-Full BAB is really a beast. It pretty much remains at a static 50% chance to hit the entire way to 20. I wouldn't expect to find any variance in the level gaps.

-Medium BAB is really pretty badass starting out... until JUST after level 10- then shit hits the fan. That's an ugly 21% at closing, so if you are GM with a melee Medium BAB character in your group (like a Rogue), remember to give them opportunities to hit things. Try presenting them with targets that play to their strengths so they don't feel left out.

-JEEZ! Even with a +2 weapon and +3 in Strength (or dex if using weapon finesse), a low BAB character CAN NOT (without a natural 20) hit a L20 creature. The lowest AC in the Pathfinder Bestiary is 6 and it's HIGHEST roll possible is a 35)

-I know characters at 15th level and above might have more than a +3 in a stat. I know they might have more than a +2 enchantment bonus from their weapon. Some skills give bonuses. I was just using a baseline for the entire party. A melee character might have a better to hit, but that was just my baseline.



Hope you guys enjoy!
(Credit me if you use this)

2 comments:

  1. Thanks to your charts, I was able to calculate my DPR as bow-wielding Alchemist today. Thank you!

    ReplyDelete
  2. Beautiful analysis—just what I was looking for!

    P.S. Your blog is very nicely lain out (at around 70 characters per line). Kudos.

    ReplyDelete