Flanking Redone

[Yakk]

So I don't like the Civ4 BTS flanking system. I don't even like the base Civ4 flanking system!

This is an attempt to redo it.

Flanking is changed from a percent chance to a bonus. This bonus is applied to the unit strength when you are making flank checks.

Most flanking units have a unit they attempt to flank at. Call this the flanking target.

At the start of combat, units with flanking attempt to engage their target of choice, rather than the unit that is opposing them.

AttackerStr+Flank% vs DefenderStr is rolled. If the attacker wins, the attacker has bypassed the Defender.

Next, the Defender cavalry can attempt to screen the attack -- get in the way of the attacking cavalry. Roll AttackerStr+Flank% vs the best DefenderStr+Flank%.

If the attacker wins both the initial Flank and the Screen contest, it gets to fight the target it wants to flank.

If the attacker wins the initial Flank, but loses the Screen contest, it gets to fight the screening defender. This battle is a mobile battle, and both sides continue to add their flanking chance to the fight. (Otherwise, a high-flank-percent defender could be screwed by being the designated screener)

If the attacker loses the initial Flank, it fights the initial defender.

The fight then proceeds.

When the attacker takes it's last damage from a killing blow, there is another flanking contest. If the attacker wins, it disengages: a final SCREEN check is done to see if the disengaged units are trapped and killed regardless.

...

In short:

FLANKING contest between attacker and best defender
SCREEN contest between attacker and best screener
The above two contests determine who the attacker ends up fighting. SCREEN contest doesn't occur if attacker loses FLANK battle.

Normal battle then proceeds, however if it is a battle as a result of a screen check, both sides continue to add their flanking bonuses to the fight.

If the attacker loses the battle, FLANK contest between attacker and defender. If the attacker wins this contest, it disengages.

Then SCREEN contest between attacker and remaining best flanking defender (other than the existing one). If this SCREEN check wins, attacker is killed.

....

So now you can defend against attacker's cavalry in two ways.

First, a strong anti-horse unit is difficult to disengage from: the intial FLANK contest. So bringing along pikemen actually helps defend your catapults!

Second, your own cavalry has a chance to intercept the attackers. If your cavalry has high flank promotions, it has bonuses to intercept: and if it is strong, it will pound the attacking cavalry into the dust.

So FLANK% is now useful for both attack and defense.

...

Flank modifiers will be upped, as they are no longer absolute percentages. Now much is something I'll have to play with. I'm thinking 3 times as high?

Notice that even with very high flank modifiers you still won't retreat reliably, because the defender can have the same high flank modifiers.

...

What should happen if there is no catapult to attack -- should there still be check to go into a screen battle? The attacker could be worse off because the defenders flanking abilities are much stronger...

Then again, there is the problem of an attacking stack being weaker because it brings along catapults, which allows the attacker to fight the cavalry and ignore the pikemen.

Hurm.

Thoughts?

 

[searcheagle]

So I don't like the Civ4 BTS flanking system. I don't even like the base Civ4 flanking system!

Civ does not make a true attempt to involve flanking in the game. The game does only includes "flanking" as another variable for combat, in the same way that the "ambush" tactic does not hide the unit.

This is an attempt to redo it.

Flanking is changed from a percent chance to a bonus. This bonus is applied to the unit strength when you are making flank checks.

Most flanking units have a unit they attempt to flank at. Call this the flanking target.

At the start of combat, units with flanking attempt to engage their target of choice, rather than the unit that is opposing them.

AttackerStr+Flank% vs DefenderStr is rolled. If the attacker wins, the attacker has bypassed the Defender.

Next, the Defender cavalry can attempt to screen the attack -- get in the way of the attacking cavalry. Roll AttackerStr+Flank% vs the best DefenderStr+Flank%.

If the attacker wins both the initial Flank and the Screen contest, it gets to fight the target it wants to flank.

If the attacker wins the initial Flank, but loses the Screen contest, it gets to fight the screening defender. This battle is a mobile battle, and both sides continue to add their flanking chance to the fight. (Otherwise, a high-flank-percent defender could be screwed by being the designated screener)

If the attacker loses the initial Flank, it fights the initial defender.

The fight then proceeds.

When the attacker takes it's last damage from a killing blow, there is another flanking contest. If the attacker wins, it disengages: a final SCREEN check is done to see if the disengaged units are trapped and killed regardless.

...

In short:

FLANKING contest between attacker and best defender
SCREEN contest between attacker and best screener
The above two contests determine who the attacker ends up fighting. SCREEN contest doesn't occur if attacker loses FLANK battle.

Normal battle then proceeds, however if it is a battle as a result of a screen check, both sides continue to add their flanking bonuses to the fight.

If the attacker loses the battle, FLANK contest between attacker and defender. If the attacker wins this contest, it disengages.

Then SCREEN contest between attacker and remaining best flanking defender (other than the existing one). If this SCREEN check wins, attacker is killed.

....

So now you can defend against attacker's cavalry in two ways.

First, a strong anti-horse unit is difficult to disengage from: the intial FLANK contest. So bringing along pikemen actually helps defend your catapults!

Second, your own cavalry has a chance to intercept the attackers. If your cavalry has high flank promotions, it has bonuses to intercept: and if it is strong, it will pound the attacking cavalry into the dust.

So FLANK% is now useful for both attack and defense.

...

Flank modifiers will be upped, as they are no longer absolute percentages. Now much is something I'll have to play with. I'm thinking 3 times as high?

Notice that even with very high flank modifiers you still won't retreat reliably, because the defender can have the same high flank modifiers.

...

What should happen if there is no catapult to attack -- should there still be check to go into a screen battle? The attacker could be worse off because the defenders flanking abilities are much stronger...

Then again, there is the problem of an attacking stack being weaker because it brings along catapults, which allows the attacker to fight the cavalry and ignore the pikemen.

Hurm.

Thoughts?

I don't think this will catch on. It will make the game much more tactical than the game has been. It also really complicates the game. I would prefer to get the combat closer to the current system.

 

[Yakk]

What the user would see is simple.

You'd attack. Sometimes when you attack with a flanking unit, you'll avoid the main defender, and fight the screen and/or siege weapon instead.

When defending, having flanking cavalry around to screen your siege weapons against flank attacks will be important.

That's it -- the details of how the fight works are just details. The actual flow of combat in civ4 is very similar, and you can ignore it just as much.

Factoring in the effects of flanking to your victory chance when you right-click will take a bit of work. Displaying your "flank chance", ie your chance to actually hit a siege weapon instead of the displayed target, would be about the only thing you'd have to add to the UI.

The implementation details above where probably "too much information" -- I was checking to see if there where any errors in the flow that would lead to problems. I did spot a few of them.

To be clear:

Civ does not make a true attempt to involve flanking in the game. The game does only includes "flanking" as another variable for combat, in the same way that the "ambush" tactic does not hide the unit.

I dislike the existing Flanking because it is mechanically horrid.

First, there is nothing defenders can do about flanking attackers. The defender's stats don't change the chance that the attacker manages to retreat at all.

Second, it is ridiculously inefficient at actually making your unit survive in most contexts. A combat boost usually works, except in the case where you are trying to get at catapults.

Third, there is nothing the defender can do to defend it's catapults against a flanking attacker. Getting to the point where suicide attacking cavalry will lose the fight is relatively easy -- after which, there is nothing you can do at all.

I don't like those properties of the "flanking" mechanics in civ4.

The above is my attempt to fix that.

First, you can "screen" against flankers using your own flankers. This matches "historical" uses of mobile troops, and encourages mixed arms tactics.

Second, your chance to flank is a standard Civ4 contest. This means that strong anti-cavalry units can reduce the ability for the defenders to flank them. Having pikemen along to stop knights from flanking actually works -- the more anti-cavalry your unit is, the better it is at blocking cavalry.

Because all of this uses the standard Civ4 combat model, it extends organically between eras. Your tanks can guard your flanks against enemy tanks, both protecting your artillery and finishing off wounded enemy tanks.

 

[Yakk]

Ok, KISS: (Keep It Simple, Stupid)

There are 2 flank checks at the start of each attack by a flanker. These determine who will defend against the attack.

The first lets the attacker change it's target from the best defender to the worst defender of the target unit type. (the attacking unit always attempts to attack the flank target if it can).

The second is by the best defending unit (including flanking). It lets the defender veto the attackers target, and instead fight the screening unit. (The defending unit auto-vetos if it is a better defender than the unit the attacker is currently going after).

Then, if the attacker loses the fight, it makes a flank check against the defender to disengage, then a screener makes a flank check against the attacker to prevent disengagement.

...

Result: Flanking now follows the Civ4 "combat strength" model. An infantry attacked by a chariot results in the chariot having serious problems disengaging.

You can actually defend your siege against enemy mounted units with anti-mounted units and your own 'screen' of flanking cavalry. This defense isn't perfect, but the better your screen and anti-mounted, the stronger the defense of your siege train.

All of this happens automatically when you attack, and I think I can make the SDK calculate the right odds of success.