Symmetry

When discussing symmetrical maps, forgers think of maps where both halves are mirror images of each other. But symmetry is more than just the layout of a map. At the core of symmetry is the forger’s ability to enforce the rules of the game. And I think it can help to see how symmetry is used in sports to better understand how and why it is used in level design.

Symmetry In Sports

Basketball is a fully symmetrical game. From the initial toss of the ball at the center of the court (the initial rush) to the conclusion of the game, each team is afforded exactly the same opportunities. The game is played on a fully symmetrical court. The reflective translation of the court’s layout provides equal distance and equal effort to each team’s hoop regardless of where you begin along the court’s center plane. All of this creates pure symmetry in the Game Play itself to ensure unquestionable fairness through continuous equal opportunity to score, since both teams can score at any time.

Baseball is a fully asymmetrical game. Each team plays only one role (offense or defense) during a single Round, switching roles every Round. Two consecutive Rounds are called an Inning. The game is played on a dramatically asymmetrical field, where defense has free roam everywhere except the batters’ box, and the offense has both exclusive access to the batters’ box and shares only the Paths between the bases with the defense. In Baseball, there is never equal opportunity to score at any one moment in time, for only the offense can score. Rather, opportunity to score is balanced through the aggregation of any one pair of Rounds.

Football is a blend of symmetry. Asymmetrical properties of the game include a first and second half, essentially two Rounds. Each half starts with a kick off in which each team is the kicking team only once. The teams also change ends of the field to balance any benefits that the wind may offer. And each team plays a role of offense or defense, where the ball is owned by the offense. Symmetrical properties include the field layout, both teams can score on any play, and the asymmetric roles can change any number of times for any length of time.

Pool is the fourth example of a sport that I want to introduce, because it has a very interesting dynamic that is also found in a couple of Halo Game Types. Like Football, Pool is a blend of symmetry. One person plays at a time (one person is offense at a time and only he can score), and the changing of the roles (who can be the shooter) can change any number of times and at any time. But what makes Pool very different is that the player who is shooting is winning, because until he misses and loses his turn, he is the only person who can score.

Symmetry In Halo

When we talk about symmetrical maps and asymmetrical maps, we are talking about how the Geometry, the Spawns, and the Weapons are laid out to establish either perfectly equal opportunities to yield an unquestionably fair game; or to establish the two ends of the map uniquely for the roles of offense and defense, regardless of how different the two ends compare with each other. In this respect, it is actually going to be easier to discuss asymmetry in Halo first, because there are just a few true asymmetrical Game Types that we need to cover.

One Flag, One Bomb, Territories, and Invasion are all examples of fully asymmetrical Game Types. Like Baseball, the goal is never to establish equality of play, but to promote unequal Game Play through team roles, while seeking fairness through the pairing of complimentary Rounds. For these Game Types, map symmetry is neither required nor desired; but rather dramatic asymmetrical Geometry supporting the role.

Static Spawning is required; yet the Spawn layout for each team is driven exclusively by the surrounding Geometry and not in any way by each other. Weapons can be placed in the middle of the map for an initial rush, but this is not necessary. Instead, each team has their own weapons and vehicles uniquely chosen to aid them in their roles.

For Invasion, the asymmetry goes a step further, and each team plays Invasion as a unique race depending upon their role on the given map; and the weapons and vehicles for each role match the race for that role.

Juggernaut and Living Dead are the most extreme of asymmetrical Game Types that I can think of in Halo. Not only does each team have unique roles, but the population of each team is different and dynamic. In each Game Type, players of one team can switch to the other, and the two teams are typically unbalanced.

It is these Game Types that I feel Pool makes the best analogy. So long as a player is a human in a Living Dead (Flood) Game Type, he is winning. Why do I say that? Because he can rack up pretty much endless kills. Once he becomes a zombie (or the Flood in Halo 4), there are only so many points that he can accumulate.

The same is true with the Juggernaut. So long as a player is the Juggernaut, he can score.
For these Game Types, there are no symmetrical requirements for the map. Dynamic Spawning is best; and there are no initial rushes for power weapons, because the weapons used are restricted to each team’s role.

All other Game Types are symmetrical, because they require both teams to continuously play the dual role of offense and defense, just like in Basketball. And it is this dual role that requires equal opportunities at all times in order to establish fairness of Game Play. But as with any rules, if you can make the Game Type play better in other ways, you should.

Slayer and all of its variants are symmetrical Game Types for the reasons given above. The key difference between the Slayer variants and other symmetrical Game Types is that Slayer has no objective.

CTF, Neutral Flag, Assault, Neutral Bomb, Ricochet, and Stock Pile are all examples of symmetrical Game Types for which the objective has a corresponding goal that is fixed to the bases; and with the exception of some Stock Pile implementations, their objectives never move across the map during Game Play.

KOTH, Odd Ball, Land Grab, Head Hunter, and Extraction are all examples of symmetrical Game Types for which the objective moves across the map during Game Play.

Categorizing the symmetrical Game Types like we did shows us patterns common between various Game Types. And those patterns have differing levels of needs for symmetry. What works for CTF will work just as well for Ricochet for all the same reasons, but not for KOTH or Slayer. So let’s look at how to forge for these Game Types.

Symmetrical Maps

Symmetrical maps come in two flavors.

Reflective Translation is what we would call a mirror image, where a map is divided down the center and each half is a reflection of the other across the center plane. This is the more common form of symmetrical Geometry, but it carries the stigma of being too simple, too artificial, and too symmetrical to enjoy. Some maps, like Narrows, Haven, Construct, and Countdown, can pull off Reflective Translation so well that the symmetry seems natural and compelling. (I will talk more later about why they succeed so well.)

Yet, players love asymmetrical maps, because they look more natural – they are more interesting to play on. You can forge a symmetrical map and try to make it look asymmetrical by using different materials on each half. I saw one map where one base was forged out of rocks, while the other base was forged from blocks. They were Geometrically identical, but they looked very different. This approach also helps with orientation, because a player can identify which end of the map they are on by the materials surrounding them.

Another approach to hiding symmetry in a fully symmetrical map is to forge a Rotational Translation map. This is a map in which both halves of the map are identical to each other, but rotated 180 degrees around the center of the map. Asylum was the best example of this type of symmetry. Both teams saw exactly the same terrain before their bases – rocks on the right, and an open area on the left. Traversing either side of the map leads to different terrain as you cross the map’s center plane.

Rotational Translation maps fall short in one way, however. While any point along the center plane is equal distance from each base, the differences in terrain prevent them from being equal effort from either base. If a Hill, a Territory, Odd Ball Spawn, or a Head Hunter goal is to be equal distance and equal effort to both teams’ bases for a fully symmetrical experience, then they must be forged along the center plane of a Reflective Translation map.

Deciding The Map’s Symmetry

At this point you understand the need for full symmetrical Game Play to establish fairness for symmetrical Game Types; and that forging the symmetrical Game Types that have moving objectives requires both equal distance and equal effort from each teams’ bases. But is it truly practical to expect the majority of Game Types to be offered only on Reflective Translation maps? The argument would come down to how much fun is lost to the symmetry? And this in turn takes us to the Football analogy – can we forge a blend of symmetry to make these Game Types more interesting and fun to play?

Reflective Translation offers perfect balance and ultimate fairness, but nearly always at the price of boredom. Rotational Translation offers perfect balance and ultimate fairness so long as the Game Type doesn’t require moving objectives across the center plane, and to some degree a touch of boredom (symmetry cannot be hidden completely). And asymmetrical maps offer the best opportunity to captivate the imagination of players, but offers the forger the greatest challenge to achieving near balance and fairness. If you choose to implement any symmetrical Game Type on an asymmetrical map, realize your number one driver is to create an environment so thrilling to play on with so little imbalance that what imbalance your map has is easily overlooked. So long as you achieve a great experience and you truly minimize imbalance, your map will be taken seriously.

Regardless of the map’s symmetry or lack there of, there are important considerations to keep in mind.

Spawning

For those symmetrical Game Types that have base fixed objective goals, Static Spawning is required regardless of the symmetry of the map. This ensures that a team will always Spawn near their team’s base and never at their enemy’s base.

For all other symmetrical Game Types, Dynamic Spawning is usually preferred. In fact, I would argue that Dynamic Spawning is necessary for asymmetrical maps, because it helps balance access to key parts of the map. If there is a benefit to north end of the map, it wouldn’t be fair to allow only the blue team to spawn at that end all the time. Dynamic spawning helps balance out the spawning across the map and all the opportunities that come with it.

Minimize Imbalance

If you choose an asymmetrical map, you will need to work extra hard to minimize imbalance through out the Game Play. This is where things can get tough. While testing you will not be able to prove you discovered every imbalance your map has to offer. You can only discover imbalance, but you can’t know what it is you haven’t discovered yet.

Regardless of the symmetry of the map, initial rush for Power Weapons should still be on your map, and they should all be at the very least equal distance and as much equal effort from initial Spawns as possible.

Moving Objectives

Let’s step back and talk about the difficulties of forging the symmetrical Game Types whose objectives move across the map. We talked about how if you use a symmetrical map for the purpose of fairness, then it must be a Reflective Translation map, because Rotational Translation maps don’t offer equal distance and equal effort together. But quite often even the perfect Reflective Translation map will make a Game Type like KOTH boring, because the Hills are always on the center plane of the map. So if you are like me you want to scratch the entire idea of attempting to forge a symmetrical map to forge these Game Types on. That leaves you with asymmetrical maps, or maps that are more interesting. This forces you to focus on making the map so interesting to play on that any imbalance that may be perceived is accepted as necessary to make the Game Type playable – to make it a lot of fun!

A far more interesting experience is an apparent random scatter of objectives across the map. For this reason you do not want Static Spawning, because you never want one team to have an advantage over a given Hill, Territory, or zone. Dynamic Spawning is best in these cases to allow players generally equal access to all parts of the map upon Spawn, and it also penalizes death by making the player spawn further from the action.

In these kinds of maps, you may also want to consider where you place the power weapons. If you place them away from the objectives, you tend to increase the opportunity for Spawning players to acquire them. This can help prevent the game from turning lopsided.

Additionally, if a power weapon spawns at a distance from a Hill, then a spawning player may be torn between trying to take the Hill quickly or rushing the power weapon to help him take the Hill a little later. These kinds of difficult decisions can make your map more interesting to play on.

Summary

Symmetry is a key to enforcing the rules of a game and fairness of opportunities.

Making a Game Type enjoyable to where it becomes truly playable is just as important if not more so.

In each Game Type, there are Spawning rules and other formulas you need to follow to have your map taken seriously.