Thursday, August 12, 2010

MyD20 Lite: The Math Behind The Monsters, Part Three...

Good Afternoon, All:

In this third and final post on the "Math behind the Monsters" series for MyD20 Lite, we are going to look at the damage that monster inflict. Toward that end, I simply wanted to recap some the base assumptions I used.

  • I used the Priest and Rogue's hitpoint values as the average for characters at each level.
  • I assume that the average encounter lasts three rounds.
  • I assume that the average monster successfully strikes once, maybe twice, per round.
  • The last two assumptions indicates that a monster may hit as much as six times in an encounter, and so melee dmg should take that into consideration.
  • For special abilities, I assume that there are four levels of damage: Least, Minor, Moderate and Major. These correspond to one-sixth, one-quarter, one-third, and one-half of an average character's hitpoints at that level.
  • The corrolary to the previous assumption is that a monster can only apply special ability damage once per round.
  • For ongoing damage, I assume that the average character will likely make their save within the first two-three rounds, but could go on for a few more rounds. Therefore, damage associated with a special ability that provides ongoing damage should use the values for the Least Damage (one-sixth of a character's level).
  • For single damaging attacks, the usual damage should be the moderate damage value (one-third of a character's level in HP), since an encounter averages three rounds.
  • For devastating single damaging attacks, the special ability should use the major damage value (one-half of the hitpoints of a character of the appropriate level), but should only be able to be used once per encounter.
  • For annoying special attacks, the usual damage should be the minor damage value (one-quarter of a character's level in HP), which will leave a character with a quarter of his hitpoints at the end of an encounter, should he fail every saving throw.
  • I assume that the average character will make half of his saves, given the means by which we calculated the Save DC values. Thus, the impact of the above will be halved. i.e. He can make it through two encounters against a suitable opponent before he is left on the edge of survival and required to use resources he's gathered over the course of his adventures.
  • Finally, I assume that this will make combat more risky and challenging, but I also assume that players will then rise to the occasion and play either with more creativity or with more consideration for alternative approaches to resolving scenarios other than combat 100% of the time.

With the above in mind, I came up with the following relatively huge table. Starting from left to right, the table covers the following evolution:

  1. Hit Dice are converted to PC Level using the table I provided in the first post of this series.
  2. PC level is then converted to average PC hitpoints, using the Priest as our basis.
  3. I then calculate the Least Value, Minor Value, Moderate Value and Major Value for each level by dividing by 6, 4, 3 and 2, respectively.
  4. I then converted each Value (which are hitpoints) into a die range by dividing each value by 3.5 and assuming that many d6. At the lower end of the table, I handwaved a few d8s, d4s and d3s to cover duplicates and better match those lower values. This gave me Least Damage, Minor Damage, Moderate Damage and Major Damage by hit dice.
  5. Assuming that there would potentially be six attacks per encounter that land on a target, I took the Least Value and subtracted four from it, to simulate the average Medium creature attack of a d6. This gave me a rough damage adjustment by level (Rough Dmg Adj).
  6. Finally, noting that I didn't want to start with a negative number, and noting that we cap out at +9 for 25 HD creatures, I divided 25 by 9 to get ~2.78, which I rounded up to 3. Thus, every three levels gave us a +1 increase in melee damage.

By looking at the last two columns, you can see that the suggested damage increase falls under the one-sixth calculated value starting at 7 HD, and runs behind thereafter. Therefore, I'm good with not capping the damage adjustment at a lower HD range, and just letting it run all the way up to the overall cap of 25 HD.

Table: Damage Values By HD
HDPC LevelAvg PC HPLeast ValueMinor ValueModerate ValueMajor ValueLeast DmgMinor DmgModerate DmgMajor DmgRough Dmg AdjSmooth Dmg Adj

So, what does this mean in terms of gaming experience? First, while dice pools can give "swingy" results, much like a Mage's fireball or lightning bolt will, on the average, two combat encounters with a monster of an appropriate level will be pretty rough on the characters and bring them close to death. A third encounter without using resources or taking time to recover should prove fatal to at least one character. Once players see the effects of this in play, they should hopefully think twice before jumping into combat willy-nilly. And if they do, it should get the adrenaline pumping and fuel the excitement of the scene as the combat moves toward resolution. Yes, there's the chance that "bad dice" could end a combat sooner than the players might desire, but there's an equal chance that it could be as devastating on the monster. One of the elements I like about this approach is that it allows the Warrior to excel in combat, as he is supposed to, while encouraging the Mage to stay out of combat when he can, due to the greater risk to life and limb. Will it work out that way in actual gameplay? I don't know for a fact, although I strongly suspect it will, but I'm looking forward to finding out. The math is solid, and so far as I can tell, the math backs the underlying assumptions.

What are your thoughts? Any holes in my logic that you might want to share with me, to improve the game experience overall for all involved?

Thanks In Advance For Your Time,

1 comment:

James said...

I like the new damage modifer progression. It nicely indicates an increase in 'strength' with creature hit die.

I assume you'll keep the size modifiers to damage as well (e.g. +8 for Gargantuan creatures)?

My main concern with your approach is how you account for creatures with multiple attacks (such as dragons). If the creature has a multi-attack routine like claw/claw/bite, those damage modifers, and the realtively large dice pools for higher level creatures seem like there would be a fair chance of killing a PC in a single round.

Did you factor in the effect of creatures with multiple attacks?