Sunday, January 10, 2010

Resource Theory

There are a few main types of resources that drive class abilities in most MMOs. This is a categorization of the ones I've seen.

1. Net-Loss Resource

This is a resource which, at the end of the encounter, is lower than it starts. The classic example of this is mana. Classes with mana start at full, and spend it as the fight progresses.

One of the advantages and disadvantages of mana is that all abilities are available right at the start. As well, there is no innate restriction to using any sequence of abilities, until the entire resource is exhausted. This can cause burst damage in PvP, but it does grant the character maximum flexibility to deal with whatever situation may arise.

The major problem with net-loss resources is that they are very dependent on encounter length. If the encounter is longer than the resource can sustain, the character cannot do anything. If the encounter is shorter, the resource does not constrain the character in any significant way.

Net-Loss resources work best when their rate of consumption depends on something in addition to time.

In my view, Net-Loss is the best resource type for healing, because healing depends on damage done. Additionally, having the most flexibility to deal with unusual situations is very valuable when healing.

2. Cyclical Resource

Cyclical resource are used up and renewed multiple times in an encounter. The cycle length is much smaller than encounter length.

The main advantage here is that total time does not really constrain the class. The class is constrained by ability costs and the rate at which the resource regenerates.

There are two main subtypes here: resources which start at full, and resources which start at empty. There are also systems which use a resource that starts somewhere in between, but those system tend to act like whichever extreme is closer.

Full-phase resources (such as Rogue Energy in WoW) allow characters to take immediate actions when an encounter starts. This gives the player something to do as the fight starts, but offers the possibility of burst damage in PvP.

Zero-phase resources (such as Warrior Rage in WoW) require characters to wait before they can take actions. This usually guarantees that the other side has a chance to do something, but is often not as much fun as taking actions right off the bat.

In my view, zero-phase has the potential to be more strategic, but it depends on how fast the resource is acquired, and how important the trade-off between building or expending the resource is. One example of a strategic zero-phase resource is power points in Wizard 101.

One interesting pattern often used is Two Linked Opposite-Phase Cyclical Resources. One resource starts at full, and as it is used, it generates the other resource which powers different actions. Examples of this in WoW are Rogues, where Energy generates Combo Points, and Death Knights, where Runes generate Runic Power. This patter is used because it is relatively simple, but deep enough to be interesting, and provides gameplay where several abilities are used at different times.

I think that cyclical resources are the best for both tanks and DPS characters. Generally, threat and damage depend more on time than anything else, and the other resource systems tend to be too good, or not good enough, depending on encounter length.

3. Net-Gain Resource

This, I suppose, is more a theoretical resource than anything. I'm including it mostly for completeness purposes. This is a resource which increases over time.

The only resource I can think of that does this is Land (potential mana available for that turn) in Magic: the Gathering. On turn 1, you have access to 1 mana. On turn 2, you have access to 2 mana, and so on.

This resource depends heavily on encounter length. If the encounter is long, the resource ceases to constrain the player at all.

This might actually be an interesting resource type for a PvP game. It would make the early stages of the game very strategic, while the final stages would end in a flurry, ensuring the game does not drag out.


  1. And there are cooldowns which is another type of "cyclic resource" for short cooldowns (judgement) and net-loss for long cooldowns which can be used once per fight (fire elemental).

    And I think cast time would also be a cyclic resource? It's basically the only resource a mana based damage caster has these days.

  2. I wouldn't really classify cooldowns and cast time as "resources" exactly. They're more like extra constraints.

  3. For many classes, cooldown is everything they care about.

    Paladin tanks use the 69 rotation because it gets the most out of their cooldown. They ignore their resouce.

    Enhancement shamans/ret paladins have a priority list with which they get the most damage out of their cooldowns, completely neglecting mana (at least shamans, I'm not sure about Paladins).

    And Mages, Warlocks, Moonkins and Elemental Shamans only care about DPCT. They all have infinite mana.

    For all mana based damage dealers, the mana itself is completely irrelevant. They don't care about what would be their resource. The only thing that keeps their damage in check is cast time and cooldowns.

    An exception are Arcane mages which would otherwise spam AB. And I think that class is an interesting but complicated concept. Is it better to use the highest DPCT spell and use evocate or use a spell which consumes less mana but I don't loose a few seconds evocating.

    You're probably right. And they should make mana a cyclic resource for damage dealers. With tools like Evocation, Innervate, Life Tap, etc.. And add some choices to the spells you use. As a Warlock I would love to skip Life Tap but your spells consume as much mana as they do, there's nothing you can do about it.

  4. I'd like to see an analysis of ret pallies from the viewpoint of Resource Theory. They use mana, but it does not function like mana as it does not deplete during the course of the fight. Remember, ret pallies are the only mana using dps class that doesn't have any way to increase their mana pool. (int)

  5. Another game with the Net-gain resource is the classic Risk board game. You start out with very few armies but as the game progresses you get more and more until at the end of the game you're putting down 30 armies per turn. This is true even if you're losing, as long as you can gain one piece of land per turn and earn cards.

  6. An example of net gain resources in WoW is Deathbringer Saurfang's Blood Power.

    He gains blood power at a baseline derived from Boiling Blood ticks. Unless you pull some really interesting tricks with Disc Priests, the first mark will go out at no later than 100 seconds into the fight. The second mark will go out 150 seconds in, the third 185 seconds, the 4th 210 seconds, the 5th 230 seconds, and the gap between marks just keeps closing until your raid gets overwhelmed.

  7. Shadowbane was essentially built around 'net-gain' resources - and this necessitated periodic server resets. Indeed, in all MMORPGs, your [i]gear[/i] constitutes a 'net-gain' resource - albeit on a longer timeline than a single fight.

    In terms of a single fight, it should be obvious that a 'net gain' resource has the opposite problem of a 'net loss' resource - the longer you can extend the fight, the more certain victory becomes.