The Attack State

Since we’re learning about combat design and the idea of an attack is what combat revolves around let’s take a deeper look into the Attack state and study the anatomy of an attack in general. As I mentioned before an attack generally consists of an animation. Let’s take a look at following attack animation for Ken from Marvel vs. Capcom 2

Ken Kick

This kick animation is composed of 15 frames and a 16th frame at the end showing Ken back in the Idle state. This attack along with all other melee attacks is composed of three parts:

1.   What I call the Wind Up. This is the first part of the attack where the animation has already started but the attack collision is not       activated yet. This means that a collision with the opponent during this part of the attack will not result in the opponent hit reacting       or taking damage.

2.   What I call the Threat. This is the part of the attack that actually damages or causes the opponent or target to hit react.

3.   What I call the Wind Down. Much like the Wind Up, during this part, the attack collision is not active and a collision with the       opponent or target will not cause a hit reaction.

Let’s take a look at how Ken’s attack breaks down.

KenKick_Timeline.jpg

Each of these parts serves a vital function in terms of game design. Whenever creating a new move to add to a character’s move set it is important to keep in mind the nature of each of these parts.

Wind up: In general the wind up is used to telegraph a move. In other words when a character attacks a target, the wind up is the amount of time the target has to react to the attack. The longer the wind up the better the target will be able to plan his response to that attack. What the designer needs from the wind up will depend on the type of game. For example if you’re designing a 3-D beat-em up like God of War where the player is greatly outnumbered by enemy AI it is usually desirable that the wind up of the enemy attacks are long, somewhere of the order of 2x or 3x average human response time. (Average human response time is ~200 milliseconds for someone in the their early 20s) This gives the player a reasonable amount of time to address the threat. On the other side in this kind of game the player’s standard or simple attacks should have very short wind ups (<1x average human reaction time). This puts the combat advantage squarely in the hands of the player. Making the fact that he is outnumbered an enjoyable experience.

As you can probably guess the length of the wind up can be used to define the advantageous nature of a given attack. If two attacks are executed at the same time the one with the shortest wind up will reach the threat stage and hit its opponent first. Let’s take a look at Ken’s attack versus an attack from Guile also from Marvel vs. Capcom 2

GuilePunch.jpg

Here Guile’s Wind up is only four frames long, and naturally when these two attacks are executed at the same time we get the following situation.

KenGuileAttack.jpg

We see here that at frame 5 Ken is still in his wind up while Guile has reached the threat portion of his attack. In this case Ken’s attack is interrupted and he moves from his attack state into his Hit Reaction state. Meanwhile Guile will continue with his attack and go into the Wind Down portion of the attack while Ken is hit reacting. So as you can see the Wind up of an attack can go a long way toward defining the personality of an attack.

At this point it is important to start thinking about balancing. One of the tenants of good balancing is that for every strength there should be a weakness. It’s easy to see how short Wind up times are a strength, but what should be an appropriate weakness? Well generally the attack’s effectiveness is the trade-off. Effectiveness can mean how much damage the attack deals, or how big an area the attack will influence.Moves with small or reduced wind ups can also have some kind of cost associated with them like magic points or a finite number of uses.Likewise a long Wind up can be seen as a weakness and is a valid balancing method when you want to give an attack some kind of strength.

Threat: The threat is the damage causing potion of the attack. It is the reason the player or AI chose to attack in the first place. From a balancing stand point the length of a threat does not actually play as big a role as the length of the wind up or wind down. Instead the length of the threat affects how the player perceives that attack. The idea is that while the character is attacking anything that comes near him gets hit. This gives the player a sense of safety, which makes the move feel more powerful. Because of this, moves with long Threat times are often designed to be special attacks. Moves with longer threat periods also provide bigger windows of opportunity for attacks. If an attack has a very short threat then a player would need to time the attack to make sure he hits his target inside the small time window. If the threat were longer, then even if the player missed with the beginning of the attack there is still a chance that he could hit with the end of the threat. This is especially the case when attacking enemies that are meant to be low difficulty. They can be programmed not to respond to the threat from the player, which means they’ll walk right into the attack. This will make the player feel that the attack is accessible and easy to use. Moves that feel more accessible can be important to help novice players learn the game and avoid frustration.

There is also the other side of long threat times. Should the attack fail the extra time on the threat is added to the amount of time the opponent has to respond to your attack. Furthermore if the player or AI is planning on hitting the opponent with the end of his threat, the beginning of the threat is added to the telegraph of the move, which again adds to the time the opponent has to react to the move. Also, despite the aura of safety the player feels during the threat part of the attack, it is usually the case that the player can still be successfully attacked. This attack can come from behind, or from some kind of projectile. The point is that during the threat the character is still vulnerable, and the longer the threat the longer the character is vulnerable to attacks that can penetrate his threat.

Though length is important to think about when creating the threat of an attack what is more important is its shape. The shape of the threat will determine whether the attack will be effective against targets in the air or ducking in front of you. It will determine if you can only hit targets in front of you or if it can hit targets around you or even behind you. Once again let’s take a look at Ken’s kick versus another move. This next move will be a sweep from Ryu.

RyuSweep

Here we see that Ryu’s attack is low. So what happens when we put it up against Ken’s kick?

KenRyuAttack
What we’re seeing is the first frame of both Ken and Ryu’s threat. Given these images the player would expect the collision data from Ken’s attack to be on his foot over his head, and it is. The collision on Ryu’s attack is on his extended foot. Even though both characters reach the threat portions of their attacks at the same time, the shape of those attacks will cause Ken to miss over Ryu’s crouched body, while Ryu’s attack connects directly at Ken’s feet.

Here’s another example of how the shape of the threat can be used as an advantage.

DhalsimZangiefAttack

In this case, the shape of Dhalsim’s attack (on the left) makes it so that he can hit opponents from a distance outside his opponent’s range. When it comes to the shape of an attack the sky’s the limit. Shapes can be in front or behind; they can attack above, below or all around. When dealing with three dimensions, attack shapes can be even more diverse. Take a look at these screenshots from God of War.


GofOfWar1

GodOfWar2

GodOfWar3

Creating moves with varying shapes will give the player many interesting decisions when picking an attack, and promote rich tactical situations.

Wind down: If the hit react is a reward for successfully landing an attack, then the wind down is a reward for successfully avoiding one. Once an attack reaches the wind down portion it can no longer do damage, however the attacker is still in the Attack state and does not have full access to all his actions i.e. he is vulnerable until the attack ends and he returns to the Idle state. This provides a prime opportunity for an opponent to retaliate against the attacker. Just like with the wind up a long wind down is a weakness and is a very common tool used to balance a move’s strength. In fact in most games the strongest moves are almost always accompanied with the longest wind downs.

Much like with the wind up what the designer needs from the wind down will vary greatly depending on the kind of game he or she is creating. When deciding how long the wind down of a player’s attack should be you don’t want to make it too long. At the most you want the wind down to give opponents enough time to react to the attack only if they are already in an advantageous position and only if the player made a bad decision as to which move to use. As mentioned before the wind down should be proportional to the strength of the attack, but in reality it should not be any longer than one or two seconds. Any longer than that the player might get frustrated by that move and moreover a wind down that long means that the player has to wait before he may resume performing actions, effectively halting the gameplay experience. The actual limits of the wind down will of course be dictated by the pace the designer wants to set, but this should always be kept in mind. Having said that, when creating wind downs for AI characters, extraordinarily long wind downs can be very useful tools.

When creating a game like Street Fighter where the characters involved in the combat must be balanced and on even ground, it’s usually desirable that all attacks will cause an opponent to hit react. This is offset by the small windows of opportunity that an opponent has to react and interrupt attacks (approaching 1x human reaction speed). However, in games where the player is fighting against AI’s it is common have enemies only hit react to certain attacks or not hit react at all. This is a tactic that can be used for more difficult AIs or even bosses. Consider this match up from Devil May Cry.

DevilMayCry

In a case like this, the player’s perception of the enemy being strong is enforced by not being able to cause him to hit react so easily. Even though both characters still follow the flow of the combat state machine, the machine that controls the boss may have the transitions that go into the Hit Reaction state…

CombatFSM_HitReact

…follow special rules or even be absent all together. This poses a challenge to the player by making it difficult to choose a time to attack. Normally if the player can land an attack first, his opponent will hit react, which leaves the player safe from retaliation. An enemy like this though can attack at any time. Which means the player is always vulnerable. The Player’s strongest moves usually also have the longest animation times; this leaves him defenseless also for the longest times. He can choose to engage whatever defense his Defense state implements, but unless that defense can also directly defeat the enemy, the player will eventually lose. This is a common set-up for a boss and the solution to the player’s problem is usually found in the wind down of the enemy’s attacks. Attacking while the enemy is defending should be futile by design; attacking while in the Idle state seems like the straight forward solution but using attacks that are too long will leave you vulnerable. The player can attack during the Wind up or threat part of the enemy’s attack but because it won’t get interrupted the player still needs to evade the attack. The player does not have access to his full range of actions while attacking so it’s harder to evade an attack while attacking. This leaves the wind down of the attack. The enemy cannot attack again until his wind down finishes and he returns to Idle. This is the only time the player can attack with confidence. So in these situations it can be useful to give the enemy an extraordinarily long wind down time, long enough for the player to complete several attacks giving him a clear opportunity to attack and eventually defeat the enemy.

This is one example of how you can use the wind down of an attack effectively from a design point of view.

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