Map Flow
Map flow is a somewhat subjective term. It could be defined as the sum value of the potential movements, actions and strategies a map has. Making it even harder to define, map flow also shares several elements from other map design principles. Generally, the principles have to do with layout and object placement, but they are also tied to psychology and timing. The unifying goal for all principles that make up map flow is to maximize the replay value of the given map.
General Navigation
The manifestation of Map Flow is usually thought of as an imaginary river or wind flowing through the map. Where the flow is congested, turbulent, or imbalanced is where the map will frustrate players the most in terms of navigation.
An Open Map and a Variety of Routes
If a player can see it, they should be able to reach it very easily and without backtracking. Players should be able to get anywhere in a map very quickly. The space should also include more than one way to get to and from main landmarks. These ideas promote both an immediate engagement with the map's strategies and a long-term exploration of alternate tactics.
Free Movements
Nothing is worse than running with the flag and then getting stuck on a little decorative rock that looks so nice and pretty sitting there, but is a death trap for anyone that tries to run over it. —Hanover_Fist
"Sticky" spots prevent obvious navigation when the game engine's collision detection gets in the way. This happens more often with static meshes, but can also happen with steeper sections of terrain and in tight spaces made of BSP. Make sure doorways, pathways, tunnels and crawlspaces are big enough to move through in a firefight. See also General Scale and Dimensions. Playtest these areas with the idea that players will be more concerned about combat than traveling in smooth, central paths. Playtest the edges of your pathways, extra rough spots of terrain, and the areas with heavy decoration, then place low-poly blocking volumes to replace any sticky static mesh collision and discreetly cover (or just smooth) any terrain collision you find not working well.
Dead Ends, Hazards, and Risk vs Reward
Risk vs Reward is the concept that there is a balance between the risks a player must take and the rewards the player will recieve if those risks are succesfull. A hidden deathtrap in a main corridor or a safe pile of powerups in front of a PlayerStart are examples of situations that are out of balance.
A dead end can either enhance or ruin a map depending on the situation. Dead ends can provide a focus point for combat if they are used to hold control points and flag bases in CTF and DOM gametypes. The worst thing you can do as a mapper is force the hunted into an area of no escape; waiting for death, while the hunter launches projectiles into the dead end. This requires no skill for the hunter and it aggrevates the hunted. Provide extra ways either in or out of the area or make the dead end quick to reach and retreat from. Above all remember to balance the risk with reward by placing a strong powerup or weapon inside a dead end. Hazards suchs as open lava pools, dangerous heavy machinery or large drop-offs should be given the same Risk vs Reward considerations.
Interconnectivity
Interconnectivity has to do with the varied connections between the areas of a map. Having more than two ways in or out of a space ensures multiple tactics in Navigation. Players will be aware of these extra routes as escape routes, ambush points, sniper positions, and usable cover. This principle can also eliminate "perfect" sniper positions by forcing the sniper to look over their shoulder. In the extreme, this principle can be overdone, making the map lose some of the variation or definition between areas, as if it were only one space.
Side Passages, Escape Routes, and Cover
While players move from one area to another, there will inevitably be combat. In situations under fire, players seek cover to block the line of fire of their opponent, while lining up their own clear shot. Long stretches of space without usable cover, side passages or corners will frustrate players in the heat of combat. Useable cover includes features a player can use to block enemy fire, and usually block their line of sight as well.
Rewarding Special Moves
Special moves such as the Translocate, Dodge, DoubleJump, ImpactJump and LiftJump use a higher than novice skill. Couple these skills with a knowledge of a map that rewards special moves, and players are given the opportunity to PWN (dominate) unsuspecting opponents. Rewards for such moves can be everything from access to a shortcut, to getting them through a narrow escape route. The various Jump moves can reward players by getting them to an out-of-reach ledge with a special item on it.
The Z-Axis
These are the elements of the layout that take advantage of vertical site lines, vertical movement and vertical combat. Z-axis has a page all to itself.
Predictability
Players in any game require some certainty in order to plan ahead. In Map Flow, certainty comes from predictable events and structure.
Framerates and Optimization
Before you start building a map, decide the maximum players it should hold in the heat of battle. This is the single most important factor in framerate perfomance, given large overhead for player models, weapons fire, personal effects and gore. If the map holds too many players fighting in one area, your map's performance will suffer and so will the players; especially online. Optimize thoroughly to ensure the player's experience is smooth throughout and your carefully timed elements are not interfered with.
Balance of Power, No Perfect Sniper Positions
Here a map with good flow is essentially balanced for combat between players. In such a map, no player will accidentally gain a severe tactical advantage or disadvantage. No sniper position will be "perfect"; that is, easily defendable, difficult to assault. No spot on the map should be an easy target without sufficient reward value. Of course, no team game maps should have inherit advantages for one team over another. Within this balance, provide some variety of PlayerStart positions, including a safe spots or item stashes as well as hazardous or frontline areas. See also Placing PlayerStart
Sound cues, Triggered Events, and Item Placement
Use triggered sounds like water puddles that splash or carefully place items like health vials to create sound cues near special areas. Any detectable event that is triggered by player movement through a space will work. Doors often serve this purpose well, as they usually make distinct sounds and they delineate two different areas. These are great ways to add potential risk to high-traffic or particularly attractive areas. See also Triggering Sounds and Inventory Item Placement.
Patterns of Rhythm and Form
Players recognize patterns easily and use them to their advantage. A regular series of spaces or a regular measure of time can allow players to predict each other's movements or changes in the environment. A regular loud sound can cover the sounds of a player's actions. After going through a series of rooms with the same shape, a team can hone their tactics as they advance. A symetrical map can help players learn a large map in half the time.
Clear Goals
It shouldn't be a complete mystery how to succeed in a map. If there are strategically critical positions to hold, they should be almost immediately obvious to the player entering the map for the first time. A player will want to devise successfull attacking or defending plans while getting the first impressions of a map's layout.
Building Goals Towards a SuperGoal
A heightened sense of achievement comes from an accumulation of efforts. If a map's design uses a progression of actions or challenges to achieve a climax with sufficient reward value, the players will feel more involved and satisfied with their efforts. The rewards can either help the player or hurt their opponent. The Assault (AS) and Onslaught (ONS) gameTypes have this progession of goals clearly built into the rules of the game, but other gametypes can impress players by using the same idea in unique ways.
Action
Action is change over time and is a term used to describe conditions changing at an irregular pace or direction. Whether the players change or the environment changes, action is what players need to experience in order to feel satisfied with the game. In many ways, the principle of Action conflicts with the principle of Predictability, and a balance must be struck. Although action typically implies movement, any apparent change qualifies as action.
Variation in Space and Timing
Variation is a designers best friend. Here it's the player's perpception of the environment that changes. As a player is aware of the map, their perpection of the space they're in changes when they move from space to space. The change from a narrow hallway to a wide room gives a perceptual change that registers as action to the player. Random timing can increase tension or danger and serve to make experiences more organic. An irregular water drip will give a listening player a greater sense of purpose, to find a pattern, and a greater sense of satisfaction when they come to the conclusions the pattern is complex or there is no pattern.
Keep Up the Pace
Keeping the pace alive is an old secret to success in performance. Your audience, the players, don't want to wait for the next thing to happen, the next thing should be waiting for them. Make sure lifts don't take too long to ride, spaces aren't too long without some change, and progressions of predicatble events don't take too long to complete.
Use of Layout to Create Suspense
One of the most subtle forms of action is a change in mood. The player can be in the most familiar surroundings and yet their experience can change drastically by their level of anger, joy or fear. By making sure a sniper position includes an alternate entrance that just happens to be behind the sniper, you've created tension. By giving the opponent several routes to attack the base, you've created potential fear for defending players. By having regular intervals or events end in a strange or unpredictable way, you've created suspense for the player paying attention.
Suprises and Discovery
No player wants to experience "the same old thing". If suprises can happen and the player can discover new features of the map, the impulse will be there to replay the map. While a suprise shouldn't happen so often as to become ordinary, it will have to be noticed to be effective. In performance, the promise of suprise and discovery is called, "the hook". The hook can be anything from a cryptic map description, to in-game clues, to blatant advertisement of a secret in the map.
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Discussion
SuperApe: What do you think?
Kedren: I think it sums things up very neatly.
