EPTThe first, most obvious characteristic of money resources is how many there are. More resources create a more complex game; Halo Wars (one of the only successful console RTS games) has only a single resource, where Age of Empires has four. Halo Wars is perhaps the simplest RTS game you will ever play; Age of Empires is among the most complex. Many RTS games, however, prefer a two-resource system in which one is the primary resource (useful by itself, and required for everything) and the other is a secondary resource (only required for some things, and only usable in combination with the primary resource).
Details of those resources tell more about the game. Many resources are placed in base locations and harvested by workers, in which case an important number is the saturation level of that resource on one base. In Starcraft, the primary resource has a relatively high saturation level (24 workers in SC2), while the secondary has a relatively low saturation level (6 in SC2). WC3, by contrast, has a low saturation level for the primary resource (5 workers) and a high saturation level for the secondary resource (trees are everywhere in most maps). High saturation levels reward efficient worker production and economy-building; low saturation levels do not (unless taking additional expansions is very easy). Because WC3's primary resource has such a low saturation level and additional expansions are relatively difficult, the game is not especially economy-focused (lumber has a high saturation level, but lumber is only useful in combination with gold, so large lumber operations just lead to a smaller army and a huge bank of lumber). Starcraft 2, on the other hand, has a high saturation level on minerals, so constantly producing workers is a definite key to success, and economy is a large focus of the game.
Sometimes money resources are tied to other non-money resources in the game. In SC2, for instance, vespene gas is tied to higher tech plays. This causes the value of the resource to vary significantly depending on the play style the player is trying to use. Among other effects, this makes scouting much more effective in the game, thus reducing the problems associated with having a large number of units available in the game. Replaceable Parts would benefit significantly from such a system, since it is based on a premise that creates a large number of permutations in the way of possible play styles.
Resources can also have a barrier to harvesting at the beginning of the game. This could be placing them outside the main base of each player, or it could be requiring some building or other tech to harvest them (e.g. refinery). This delays that resource, thus delaying any gameplay aspects that might be tied to that resource. It also causes that resource to be more of an investment, which, like tying the resource to a gameplay aspect, aids scouting by allowing the opponent to see how much has been invested into obtaining that resource.
Finally, there are more experimental features that money resources can exhibit. What about resources that are gained based on possession of a map feature, rather than harvesting of a map feature? This presents problems like defining "possession," but it is can be solved effectively. In Disciples 2, for instance, special units (much like worker units) are not terribly useful for most purposes, but have the ability to place "rods" on the map that turn the terrain into friendly terrain (much like creep tumors in SC2). Once a resource is on friendly terrain, the player receives money from it each turn. Of course, Disciples 2 is turn-based strategy, rather than RTS, but a similar system could be instituted in real time where the resource produces x rate of income once it is in a player's possession. This type of resource encourages gameplay in which position is an especially important resource, since maintaining a resource is cheap, but obtaining it is expensive.
Many RTS's today have asymmetrical races. What about asymmetrical resources? That is to say, why not have the different races require different resources to function? This encourages a different type of gameplay in which seizing a resource is half as valuable: with identical resources for each side, obtaining a resource both allows you to use it and denies your opponent that opportunity. Now players can only obtain a useful resource for themselves or deny their opponents a resource; not both. This design presents problems, however; if these are resources harvested by workers, how can bases be designed to include the necessary resources for a given player? Including all relevant resources in a base defeats the purpose of differentiating the resources. Populating each player's side of the map with the appropriate resources similarly defeats this purpose; how often in SC2 do players attempt to steal bases from their opponent's side of the map anyway?
A better way to work out asymmetrical resources is to make them possession-based rather than harvesting-based resources like Disciples 2. Then they can be placed in parts of the map that are not clearly in possession of either player, and the player that can maintain that position is rewarded with possession of that resource. Or, if we still want to use the harvesting kind of resource, then different bases around the map must provide different resources, and be placed in positions that are not clearly associated with either player. This makes expansions harder to defend, thus punishing economic plays, but that can be off-set by designing expansions to be easier to defend or making them less of an investment to begin with.
So now let's add a resource system to the Replaceable Parts model created in Part Three. Resources function as such: there are four races, and each has a primary and secondary money resource. The primary resource for one race is the secondary resource for another race, and the other two races have no use for that resource. So with races 1, 2, 3, and 4, and resources A, B, C, and D, then race 1 uses A as a primary resource and b as a secondary (lowercase denoting secondary resource), race 2 uses B and c, race 3 uses C and d, and race 4 uses D and a. Starting bases possess all four resources, but all additional expansions possess only one resource, forcing players to choose what resource to focus on. Resources will be tied to different aspects of each race's strengths, much like vespene gas is tied to tech in SC2, but our model is not yet complex enough to determine to what aspect of gameplay each resource would be tied. All resources have a relatively high saturation level per base, rewarding players for playing economically and giving them greater freedom regarding the input of their economies.
This causes the strategy to vary significantly with match-up. In mirror match-ups, the resources will be shared, and the strategy will evolve like most RTS's today. in AvB, though, the players compete for resource 2 but resource 1 is only valuable to A, and resource 3 is only valuable to B. And in AvC, then all resources are entirely asymmetrical, so the only value to obtaining the opponent's resources is denying them to the opponent.
Further strategic implications of this resource system, as well as the unit customization model described in Part Three, will be discussed in future installments of this blog.
