Sunday, 12 January 2014

Ascending Armour Class for Labyrinth Lord

Yesterday I decided I wanted to get away from looking at a combat table/matrix while running Labyrinth Lord. I thought the quickest way to do this would be to just jump on to the Lamentations of the Flame Prince ascending armor class system and ditch the Labyrinth Lord descending AC system. I posed the question to G+.

What followed was a bit of a roller coaster through the world of D&D Armour Class. I discovered (with the help of others) that the basic math for working out if an attackers hits a certain AC is the same for all D&Dlikes. The only thing that changes is presentation of the Math and the values for To Hit Bonuses/Armour Types. I don't think this is news to many people, but it was enlightening for me. Apparently there is 32 possible ways of presenting the basic D&D AC math problem.

I decided I wanted to keep the Labryinth Lord values for To Hit Bonuses/Armour and adopt a way of doing the math that worked quickest/simplest for me.

It turns out my mind grasps the concept quickest and easiest when presented in the following way;

d20 + Attackers To Hit Bonuses  >= 20 - Target's AC

or

An Attacker hits when rolling a d20, and the result added to their To Hit Bonuses is Greater than or Equal to 20 minus the Target's AC.

I like having a clearly visible number for an attacker to roll for.  I can just use the Labyrinth Lord armour values, and deduct (or add if it's a negative value) from 20 to work out a target number. This retains the exact same values needed for dice rolls. An attackers needs to get to this number using a d20 and their To Hit Bonuses to hit their target.

This is an Ascending armour class system.

Having never having played 3.0, I just re-invented the wheel. Good work Michael only 14 years behind!

So, here is the Labyrinth Lord values for To Hit Bonuses for both HD creatures and PC's;

Creature HD:
To Hit Bonus:
1 or Less   
1
1+ and 2            
2
2+ and 3               
3
3+ and 4 
4
4+ and 5       
5
5+ and 6
6
6+ and 7             
7
7+ to 9         
8
9+ to 11                   
9
11+ to 13             
10
13+ to 15               
11
15+ to 17        
12
17+ to 19         
13
19+ to 21     
14
21+ and above   
15
Cleric, Thief Level:
Dwarf, Elf, Fighter, Halfling level:
Magic-user Level:
To Hit Bonus:
1-3
1-2
1-3
1
4-5
3
4-7
2
6-8
4
8-10
3
9-10
5
11-12
4
11
6
13
5
12
7-8
14-15
6
13-14
9
16-18
7
15-16
10-11
19-20
8
17-187
12
21-23
9
10-20
13
24+
10
21+
14
11
15
12
16
13
17
14
18
15
19+
16
Notes:

Level 0 humans get no To Hit Bonus.
A natural 20 always hit.

Extrapolation: 

Now all I need to do is give each PC their To Hit Bonus (derived from the Labyrinth Lord combat tables) which they can add along with their bonus from DEX/STR to any attack roll they make. Anything that they attack will have their AC listed in Ascending notation (20 minus Labrinyth Lord AC) and if the result of their d20 attack roll plus all their bonuses is equal to or above Ascending AC they have hit! No need for a table (Blindingly obvious for people already using Ascending AC)!

Further, My G+ Labrinyth Lord campaign is FLAILSNAILS friendly, so now I can use the To Hit Bonus tables above to give every player their To Hit Bonus at the start of the game (Also ensuring to REPLACE any To Hit Bonus they have brought over from another system). Whatever whacky class a player brings to the table can be slotted into one of the three PC categories and therefore Attack Roll Power will be normalized for all players, regardless of the system their PC was made in.

I think this is great because not only do I have a much quicker notation for working out if something has hit, it's super simple to normalize every players attack roll regardless of system. My ideal game system would now be super lean only using the above AC / To Hit notation, a basic attribute check system and allowing the players to bring whatever crazy class/spell/magic item/whatever else into the fray.

After all that I understand why everyone just makes their own rule sets.