Thursday 26 April 2012

1d10 design mistakes in DnD 4e - Damage calculations

Dungeons and Dragons 4th edition uses a fairly simple system for determining combat outcomes. A 20-sided dice roll determines if an attack is a miss, a hit or a critical hit. For a hit, damage is then rolled using various dice depending on your weapon and for a crit you always do maximum damage.

As combat is often a key dramatic part of game play, player enjoyment may be deeply linked to how combat results play out. It is therefore unfortunate that the game system has a number of design mistakes.

1) The less powerful your weapon, the more likely you will match 'critical' damage on a regular hit.

For example, with a dagger a critical hit can not be distinguished from a regular hit in 25% of all cases. This undermines the dramatic effect of critical hits.

This could have been addressed by placing critical damage outside the range of normal hits or by adding additional effects. Some efforts have been made towards that goal by giving extra effects through feats, powers or magical weapons but at low levels the reaction to a crit may often be 'meh, whatever'.

2) The higher the level of power you are using, the stronger your damage will trend towards the average.

This is quite silly as it slows down game play while players tally ever increasing number of dice rolls while at the same time making it less dramatic by making most outcomes fall in a small expected range.

At level 1, a character might roll 1D12 for damage and see maximum damage in 8% of cases - it is a completely flat distribution. At level 9, the same character rolls 3D12 and sees the maximum results in only 0.06% of cases (1 out of 1728)! Thus it is more than two orders of magnitude less likely that you will see the most powerful outcome.

As your powers increase, you will become average.
More after the break.

At the very high end, this becomes so ridiculous that it is a wonder they even ask people to roll the dice. A notable impact of this ever-steeper bell curve is that the only realistic way of getting maximum damage is to roll a critical hit, thus encouraging striker characters to do everything they can to increase the default 5% chance.

Count to 65 again

This could have been countered by reducing the number of dice and adding a fixed bonus, thus limiting the range of outcomes, eliminating the tail of annoyingly poor results at the left side of the bell curve and maintaining a more desirable spread for dramatic effect.

Another design approach could be to use a dice pool where higher level powers roll more dice and the player picks the best results, so for example a 3D12 attack might be replaced with a 4D12 roll where only the best three results are selected. Players are faster at eliminating low rolls than at adding multiple dice so the extra dice do not slow the system down too much.

A third approach is to re-roll max results and add the new roll to the original. Thus a roll of 3D12 where the dice comes up 1, 7 and 12 would result in the 12 being re-rolled and the total becoming 1+7+12 plus the re-roll result. This slows the system down further but adds a level of excitement to rolls.

It also makes having more dice much more powerful, especially if they are 'small' dice (say 4-sided or 6-sided) rather than 'large' (10-sided or 12-sided). However, this really undermines the effect of critical hits as they may start doing less damage than regular hits with lucky damage rolls.

3) Too many conditional modifiers that can't be pre-calculated.

Having a single damage modifier on your character sheet that is derived from stats, feats, enhancement, item bonus and any number of other modifiers is fine. It is easy to add a dice roll to a single fixed base value.

However, when there are multiple conditional values that must be determined for every single attack the system slows down considerably. For example a character may do an attack that does extra damage if no creatures are adjacent to the target, if no allies are closer than the attacker and if the target is vulnerable to one of several damage types.

Each condition is evaluated separately and has different associated damage modifiers, increasing the risk of mistakes and the time needed to correctly calculate damage. The problem is aggravated by the variety of durations (until end of your turn, until end of next turn, until end of enemy next turn, save ends, next attack that hits and so on) which must be kept track of as players struggle to remember which effects are still active.

Such as design is justified only if the difference from each modifier is large enough that it materially changes the outcome of the battle. However, for a character at paragon levels doing 50-100 damage per round it is arguably insignificant to do an extra 2 points from some special condition.

This problem could have been avoided by making most modifiers non-conditional and only applying the extra steps for very large modifiers. Durations could be simplified to always last until end of next turn or save ends.


  1. This comment has been removed by the author.

  2. Excellent article! I might have read the wrong title somewhere. It says "Damage Calculations". I thought it said something like "the better you are the more average you become" as a title. Not sure what happened, but I liked the blog/article anyhow.

  3. Thanks Zach, it is good to hear you found it interesting. I make the point about becoming average in the article but the title was always damage calculations.