Combat Mechanics - Hit Determination

Decisive Campaigns: Ardennes Offensive is the fourth wargame in the Decisive Campaign series. Covering the battles in the Ardennes between December 1944 and January 1945, it brings to life Operational wargaming by lowering the scale to just above tactical level.

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warnevada
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Combat Mechanics - Hit Determination

Post by warnevada »

Once a target has been acquired, the next step is to determine whether the target has been hit. The firing element uses Attack Points, the target uses Hit Points. There are a myriad of adjustments that are applied to both Attack points and Hit Points. They will be discussed later. The basic concept of hit determination is quite simple. The firer gets a random number from one to the final Attack Point number; the target gets a random number from one and the final Hit point number. If the firer's random number is equal or greater than the target's random number there is a hit.

This means that elements with high Attack Points will achieve more hits than those with low Attack Points. This is particularly noticeable in the game with artillery bombardments - a disproportionate number of hits are to transport elements, such as trucks and jeeps. That's because the artillery Attack Points are high and if a truck is acquired as a target it is likely to be hit since the truck's hit points are low.

There is a relationship between weapon size and hit probability. For example, if the target is man and the weapon is a 105mm gun, a round landing 3 meters away will inflict damage. But if the firing weapon is a rifle, a round 3 meters away may not even be noticed. But the strength (Hit Points) of the target should not affect the probability of whether it gets hit. It should affect what happens if the target does gets hit.

It's a complex problem. For direct fire weapons (rifles, MGs, AT-guns, etc) target size affects hit probability - the larger the target the more likely it will get hit. For indirect fire weapons (mortars, artillery) target size makes very little difference in hit probability. Perhaps there should be two hit determination routines, one for direct fire and one for indirect fire.
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ernieschwitz
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Re: Combat Mechanics - Hit Determination

Post by ernieschwitz »

warnevada wrote: Sun Jun 26, 2022 8:16 pm It's a complex problem. For direct fire weapons (rifles, MGs, AT-guns, etc) target size affects hit probability - the larger the target the more likely it will get hit. For indirect fire weapons (mortars, artillery) target size makes very little difference in hit probability. Perhaps there should be two hit determination routines, one for direct fire and one for indirect fire.
There is.
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warnevada
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Re: Combat Mechanics - Hit Determination

Post by warnevada »

Adjustments DF.jpg
Adjustments DF.jpg (340.72 KiB) Viewed 208 times
In the screen print above, the combat detail information, the line with the green arrow shows the starting Attack Points and Hit Points. The line with the red arrow shows the adjusted totals after various modifications have been applied. Below on the left are the modifications to the firing element's attack points; on the right are the modifications applied to the target element's hit points. These are not all the possible modifications, there are additional modifications which apply for special terrain situations such as height advantage/disadvantage and river crossings.

The way it is supposed to work is you start with the initial value, then each adjustment indicates a zero, positive or negative percentage which is applied to the preceding value and the new value is shown to the right.

Apparently there is a problem because some of the adjustments on the attack side are not following the rule.

The main adjustments which apply to all elements whether firing or being fired upon, are Readiness and Experience.
In this example both the firer and target received net positive adjustments, with the target receiving higher positive adjustments. As a general rule, the firer tends to receive more negative adjustments while the target receives more positive adjustments.

In this example, the firer has a 29% chance of getting a hit.
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Vic
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Re: Combat Mechanics - Hit Determination

Post by Vic »

I'll look into this for next patch. Something is fishy in the reporting there.
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warnevada
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Re: Combat Mechanics - Hit Determination

Post by warnevada »

Before launching into an examination of the various adjustments that are applied, I would like to say to those of you who are reading these posts, Vic and I would like to hear your thoughts. If you have specific suggestions, let's hear them so they can be discussed. Even if you don't have suggestions we would like to hear your thoughts on whether the combat mechanics should be revised or if you see something in the results which doesn't seem right to you.

People - This is used to differentiate the different services within the German forces: Wehrmacht, SS, Luftwaffe. Each of them had infantry units, but their training methods differed. This allows adjusting for those that are considered advantageous for combat. On the Allied side it differentiates between American and British units.

Max Attacked - This is used to simulate the case where too many attackers of a single target tend to interfere with each other. This is valid in direct infantry and armor combat, especially if all of the attacking elements are not aware of each other they may end up shooting each other. In the game the excess attacks are just penalized with an increasing penalty for each excess attack. There is no possibility of friendly fire casualties -- this would be an interesting addition if someone could come up with a way to implement it. In my opinion it should not apply to artillery bombardments because I don't believe you could have such a volume of fire that the shells would collide in midair.

HQ - This is used to simulate the beneficial effect of leadership quality and proper staffing levels at a unit's headquarters. The level is affected by the distance of the unit from its HQ; the farther the unit, the less the benefit. In this example the attacker gets an 82% increase in effectiveness. In my opinion the HQ effect should not be as high for artillery units. Let's face it, as long as an artillery unit has sufficient ammunition and the guns are maintained the HQ staffing level will not affect the results of artillery fire.

Readiness - This is combination of things which prevent an element from operating at 100% effectiveness. Fatigue is a big factor. If the element suffered a near miss, it will tend to seek cover rather than boldly moving toward the enemy. In the case of vehicles, rather than fatigue, it's how much fuel the vehicle has.

Experience - Experienced elements will be more accurate and have a higher rate of fire.

Concentric - Each additional hexside involved in the attack confers an advantage. Hexsides further from the front or main hexside confer larger benefits because they are more to the rear of the defender making it hard for the defender to defend from both the front and the rear. In this example, the defender is being attacked from multiple hexes providing a 40% benefit.

This has gotten lengthy. The defender adjustments will be covered in another post.
warnevada
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Re: Combat Mechanics - Hit Determination

Post by warnevada »

Defender Adjustments - Just as for the firing element, there are adjustments for the target.

Readiness - For the target the readiness penalty is halved. So if an element has 50% readiness, when firing it takes a 50% penalty but if it is the target then the penalty is 25%.

Experience - Same effect as for the firing element.

Entrenchment - The higher the entrenchment value the harder it is to hit. Units in a given hex will increase their entrenchment value each turn by a specific amount determined by the terrain type until a maximum value is reached provided the unit does not carry out any action. I don't know if that is true if the unit gets fired upon or gets elements transferred to it from another unit. Some hexes have on map fortifications which increase the maximum fortification value.

March Mode - If a unit is in march mode it is assumed to be bunched up rather than spread out and not in the process of entrenching which means it will be more likely to be hit. This is enforced in two ways: 1) when the unit goes into march mode it takes a 25% readiness penalty; 2) during combat it takes a decreasing penalty per the following table

MARCH MODE COMBAT MODIFIERS
Combat Round Attack score Hitpoints
Combat round 1 -90% -95%
Combat round 2 -70% -85%
Combat round 3 -50% -70%
Combat round 4 -30% -50%
Combat round 5 -10% -25%

The Attack Score penalty applies when the element is firing, the Hitpoint penalty applies when it is being fired upon.
warnevada
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Re: Combat Mechanics - Hit Determination

Post by warnevada »

The hit determination mechanics lead to a quirk. Once a target is hit then it is easier to hit again because the hit reduces the target's readiness and entrenchment values which are used in the hit determination calculation. That may be justifiable for direct fire weapons since a successful shot will be repeated but it is not justifiable for indirect fire since the firer can't see the results of the shot.

For those of you so inclined, it is possible to game the system somewhat to increase your chances of success. If there is a particularly important hex you want to take, use the following technique. Bombard the hex with the heaviest artillery unit first. Because that artillery unit has the highest factors it is the most likely to make hits. This will reduce the defender's factors making them more likely to be hit by a smaller artillery unit. Keep this up using individual artillery units rather than a single large multi-unit barrage. The defender will be in worse shape to withstand the ground attack when it comes.
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