Accuracy Modifiers & Dropoff

[bodkin]

Hello Everyone,

I'm in my first playthrough of the XCom Files and I'm a little confused by some of the weapon statistics I'm reading.

Take the PSG-1 for example. It has an aimed accuracy of 140%, so I would expect an agent with 65 firing accuracy to have an accuracy of 91%. In game, however, the shots tend to be around 70%. It has an accuracy modifier of 0.01*(Firing Accuracy)^2. I understand the calculation, but how does it actually affect the accuracy of the shot? The same agent would have an accuracy modifier of about 42% and I don't understand how these numbers are interacting. There is also something called accuracy dropoff. With a dropoff of 3, does this mean every tile away from the agent subtracts 3 from the total?

I've tried searching for the answers, but I can't seem to find anything specific. Any help is appreciated!

[Rag]

Not sure if this answers the question, but Sniper Rifles have a penalty if the target is too close (for PSG1 example the "minimum range" is 10, this means if the enemy is within 10 tiles the accuracy is worse, while when over 10 tiles it remains maximum) , sort of the inverse of the shotgun where the accuracy is better when closer for those. There is also a "sniper / spotter" mechanic in the field manual where if your agent can't see the target themselves (the enemy number is green and not red when selecting the Agent) they have -50% accuracy to their shot so can drop from 120% to 60%. Any extra details others will need to provide as that is all I know personally.

[Vakrug]

If a weapon has "accuracy modifier" then this "accuracy modifier" substitute the default "accuracy modifier" that is the agent's shooting skill.
I your case formula would be 65 * 65 * 0.01 * 1.4 = 59.15. I don't know how you get 70%... May be by sitting?

Accuracy dropoff only applies when the target is outside weapon's effective range (which depends also on firing mode (aimed, snapped...). Weapon's effective range is shown in additional info page. If not, then default values are applied, which can be seen in default values page.

Shooting accuracy is not the most obscure mechanics of this game. Soon you will have a lot "fun" when your agent fails to hit a cultist 10 times in a row with a knife, despite shown 50% probability...

[tarkalak]

Note that the Accurcay "percentage" is NOT an actual percentage.

The game shoots inside a cone centered at the target, and the higher the accuracy is, the smaller the cone. I assume that there is something like a gaussian distribution that makes shots near the target more likely, than further away.

In the case of melee, the percent is exactly the chance of hitting, but the target has a dodge chance that depends on their stats.

The game's UI isn't able to show you the real percentage in either case.

[Vakrug]

The game shoots inside a cone centered at the target, and the higher the accuracy is, the smaller the cone.

This only happens with missed bullets. Otherwise there would be no such thing as effective distance and accuracy dropoff. I wish bullets in X-COM flies like in Phoenix Point, but they not. Same goes with throwing grenades. X% to throw a grenade in the exact spot, (100-X)% to throw it everywhere else inside a circle. This is even more annoying then with bullets.

The game's UI isn't able to show you the real percentage in either case.

I would disagree with that. Ctrl+M screen, where we can see missed/hit/0dmg info, would be a perfect place to show info about dodging. Also I wish it was more easy visually and soundly distinguish between missed hit, dodged hit and 0 damage hit.

[tarkalak]

This only happens with missed bullets. Otherwise there would be no such thing as effective distance and accuracy dropoff. I wish bullets in X-COM flies like in Phoenix Point, but they not. Same goes with throwing grenades. X% to throw a grenade in the exact spot, (100-X)% to throw it everywhere else inside a circle. This is even more annoying then with bullets.I would disagree with that. Ctrl+M screen, where we can see missed/hit/0dmg info, would be a perfect place to show info about dodging. Also I wish it was more easy visually and soundly distinguish between missed hit, dodged hit and 0 damage hit.

Not true. Old XCom DOES work like Phoenix Point.
The accuracy percent is a misnomer. The "percent" shown is how big/small the cone is.
I have seen 200% and above shots miss happily at long ranges.

The stated accuracy of a shot is not the same thing as it's chance to hit - rather it defines how badly the unit can fire.

See Use of accuracy on UFOPaedia: https://www.ufopaedia.org/index.php/Accuracy_formula

[Vakrug]

Not true. Old XCom DOES work like Phoenix Point.
The accuracy percent is a misnomer. The "percent" shown is how big/small the cone is.

Oh, come on! I am, maybe, not the the most experienced X-COM player, but even I can see this is not how bullets fly...

I have seen 200% and above shots miss happily at long ranges.

This is ALWAYS due to obstacles and NEVER due to distance. Or we are playing different games...

See Use of accuracy on UFOPaedia: https://www.ufopaedia.org/index.php/Accuracy_formula

I see: Chance to Hit% = Accuracy * Kneeling Bonus * Accuracy Penalty * Weapon Firing Mode Accuracy. There is no distance in this formula!
I know, there is a section called "Use of Accuracy" where they talk about distances, but since it goes in contrary with the first part of an article, I have less faith in the whole article.

[Meridian]

If you don't believe the players, maybe you'll believe the developer.

Here's the facts:
1. there is no such thing as "chance to hit" on ranged weapons in the original xcom or openxcom... just accept it, it's the bitter truth
2. 100% is indeed absolutely misleading, we should just display 100... but because we wanted to keep the vanilla display more than we hated lying to the player, we kept the %
3. it is perfectly possible to miss a 100% shot, due to several reasons, including distance
4. it is also perfectly possible to hit a 0% shot

If you now feel like your whole life was a lie, welcome to xcom... there's many more such surprises waiting for you if you dig deep enough.

[Vakrug]

If you don't believe the players, maybe you'll believe the developer.

Here's the facts:
1. there is no such thing as "chance to hit" on ranged weapons in the original xcom or openxcom... just accept it, it's the bitter truth
...

If you now feel like your whole life was a lie, welcome to xcom... there's many more such surprises waiting for you if you dig deep enough.

How can I believe this when it is the opposite of what I experienced for many years playing original X-COM (including TFTD) for DOS on my Windows 95 and then X-COM for windows on later versions of windows? Back then, when I was young, there was no such thing as obstacles on line of fire. If line of fire existed and game says accuracy is 100%, then I always hit the target. Even if target was so enclosed with jungle bushes, that every released bullet hit the same head part over and over again. I remember my frustration about this unrealistic mechanics.
I don't know when obstacles were implemented (I rediscovered X-COM as OXCE recently), and now it is possible to miss with 100%. I finished a walkthrough of X-COM Files (1.5 month of almost non-stop playing) and I never missed a single bullet if accuracy was above 100% and there were no obstacles, no matter how far the target was. At least I thinks so, because it is very hard to determine is there is an obstacle or not on some maps. I will pay very close attention to shots on great distances during my next walkthrough. Maybe I will change my mind when I eventually miss a target when there clearly were no obstacles, but until then I am confident, that there is no hidden penalties for long shots.

[tarkalak]

How can I believe this when it is the opposite of what I experienced for many years playing original X-COM (including TFTD) for DOS on my Windows 95 and then X-COM for windows on later versions of windows? Back then, when I was young, there was no such thing as obstacles on line of fire. If line of fire existed and game says accuracy is 100%, then I always hit the target. Even if target was so enclosed with jungle bushes, that every released bullet hit the same head part over and over again. I remember my frustration about this unrealistic mechanics.
I don't know when obstacles were implemented (I rediscovered X-COM as OXCE recently), and now it is possible to miss with 100%. I finished a walkthrough of X-COM Files (1.5 month of almost non-stop playing) and I never missed a single bullet if accuracy was above 100% and there were no obstacles, no matter how far the target was. At least I thinks so, because it is very hard to determine is there is an obstacle or not on some maps. I will pay very close attention to shots on great distances during my next walkthrough. Maybe I will change my mind when I eventually miss a target when there clearly were no obstacles, but until then I am confident, that there is no hidden penalties for long shots.

Sadly, you either remember wrong (we all do), or you were very lucky back then. It is as me and Meridian is telling you from the beginning in 1992. Obstacles were there from the beginning and often I had my agents hit the window instead of the alien.

When I did play the original game 10-15 years ago I did notice that something was amiss with the percents. I missed plenty of 100% shots in TFTD from longer range.

Oh, come on! I am, maybe, not the the most experienced X-COM player, but even I can see this is not how bullets fly...This is ALWAYS due to obstacles and NEVER due to distance. Or we are playing different games...I see: Chance to Hit% = Accuracy * Kneeling Bonus * Accuracy Penalty * Weapon Firing Mode Accuracy. There is no distance in this formula!
I know, there is a section called "Use of Accuracy" where they talk about distances, but since it goes in contrary with the first part of an article, I have less faith in the whole article.

The "Use of Accuracy" part of the article is correct. Before that it shows how the final accuracy is calculated. "Chance to Hit" there is again a misnomer as it isn't the real chance to hit. I assume that UFOPaedia was written by a lot of different people with different knowledge of the underlying system, so some parts are hard to decypher.

You can experiment with it very easily: shoot 100 shots at some hit percentage and see if the result is anywhere close to "Accuracy". Then try at different range. There is a Savescumming option that allows you to have a different rng everytime you load the game.

[Meridian]

I know how it feels.
I felt the same way 8-9 years ago.

Attached is a test save, try to shoot the alien on the other side of the map.
100% accuracy, miss.
(I modified the map to not have any obstacles at all, there's only air between you and the alien.)

I could prepare a similar save also for the original xcom, but it would take 5 hours, not 5 minutes, so I'd rather not.

[Vakrug]

Attached is a test save, try to shoot the alien on the other side of the map.

WOW! Mindblowing!  Never seen that before and I played a lot. Next step is to repeat this in my walkthrough, I guess.

Sadly, you either remember wrong (we all do), or you were very lucky back then.

Seriously, I don't know what to think now. I very well remember how I trained a monster-aquanaut, that was able to 100% hit with Sonic Canon, initially with aimed shot, eventually with snap shot. And I terrorized with him aliens until T'leth mission. And he never missed, really! Jungle episode I mentioned earlier also was not a single event. This was at time when there were no limit of how high soldiers stats can go... May be someone hacked my game...

May I exploit your kindness more and ask slightly unrelated question? What is wrong with shotguns in X-COM files? If a shotgun fires 7 bullets at once and there is 50% success chance, I expect, that at least 3 bullets hit the target, but in reality it is way less. So what exactly means success hit chance for scattered ammunition? I know, there is one stat in "more info" section about bullet spreading, but I can't figure out what that actually means...

[Rag]

Here's the facts:
2. 100% is indeed absolutely misleading, we should just display 100... but because we wanted to keep the vanilla display more than we hated lying to the player, we kept the %
3. it is perfectly possible to miss a 100% shot, due to several reasons, including distance

I have had plenty of 120%+ sniper shots missing, I expect it is because there is cover in the way but usually it says there is no line of fire when that is the case so it is confusing. Like one time there was a balcony between the target and that had to be destroyed first before the shot would hit despite the shot on the target still having the same % and being allowed to be shot without a warning.

[tarkalak]

WOW! Mindblowing!  Never seen that before and I played a lot. Next step is to repeat this in my walkthrough, I guess.Seriously, I don't know what to think now. I very well remember how I trained a monster-aquanaut, that was able to 100% hit with Sonic Canon, initially with aimed shot, eventually with snap shot. And I terrorized with him aliens until T'leth mission. And he never missed, really! Jungle episode I mentioned earlier also was not a single event. This was at time when there were no limit of how high soldiers stats can go... May be someone hacked my game...

May I exploit your kindness more and ask slightly unrelated question? What is wrong with shotguns in X-COM files? If a shotgun fires 7 bullets at once and there is 50% success chance, I expect, that at least 3 bullets hit the target, but in reality it is way less. So what exactly means success hit chance for scattered ammunition? I know, there is one stat in "more info" section about bullet spreading, but I can't figure out what that actually means...

Vanilla maps were also smaller than some of the mods here. So you wouldn't have that many long range shots.

I am not a developer, so I don't know 100%. I think that it works like the normal shots - it calculates a direction in which the shot is fired and then it draws a smaller cone around it and shoots all the Pelets inside it. So they are all grouped up together. If the hit a surface that is at an angle, like the ground, they may look like they are farther away. I am not sure how it works exactly though. Merridian should know better than me.