Rocket scatter slightly weird(?)

[LordYanaek]

Fire in the Hole reduces the number of deviation rolls by 2 (from 4 to 2 if you didn't move) so if you set

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NUM_AIM_SCATTER_ROLLS=1      ;4

Then FitH will reduce it to -1! Either it will bug out or if there is a minimum set somewhere to prevent negative number of rolls it will have few to no effect.
And perfectly accurate shots all the time will definitely alter the generic balance of Rockets. No issue for me if you want to make them a superpowered weapon in your game but i would definitively remove 1 from their AoE if it's not your intention.

I actually think better accuracy with smaller AoE could be a good change, making them more reliable but not OP.

And i tend to agree with you that increasing both number of rolls and aim penalty after moving is a bit too much but let's see how they play in the context of 1.3 before calling for more changes

[JulianSkies]

* the quirk being that, sometimes, some tiles away from the centre are each more likely to be hit than the one aimed for.

I don't think this is really that strange, ultimately. If you take, say, a 30% shot with a soldier's gun, you're going to miss more than twice as often as you hit, so why not with a low chance rocket?

Not my point, it's more subtle:

1) Yes, it is more likely and should be more likely that the rocket should miss than hit the tile aimed for.
2) Further it is reasonable that the total chance of scattering any given distance (added up(/integrated) over every different possible scatter direction) can be larger than a zero scatter.
3) What seems odd is that the chance of scattering a non-zero distance in an individual direction can be higher than the chance of zero scatter.

(3) implies that the soldier has a very odd sort of 'bad aim' where arbitrary tiles which aren't the one aimed for will each be more likely than the one aimed for. Bad aim would be more intuitively modeled instead (I believe at least) where the variance of the shot increases while the profile of the shot distribution remains qualitatively similar (i.e. if it were a normal distribution for high aim then it is a normal distribution but with higher variance for low aim - not a different distribution entirely which is what we appear to generate here).

(and again not railing here for it to change as ultimately it achieves the most important objective of implementing rocket scatter and thus not just a 'I click this button and everything dies' weapon)

Took me a while to get where you're going. Basically, scatter 0 should have a higher chance than scatter 1, which should have higher chance than scatter 2, which is higher than scatter 3, which is higher than scatter 4, however, scatter > 0 has a higher chance than scatter zero. That does make sense.
However, you also need to notice that the chance to actually hit the tile you target in the blast in, in fact, always 100%. With a blast radius of 6, only hitting the absolute max scatter of 6 in the correct diagonal will make it not hit the tile.
So wielding a weapon that will randomly scatter in any given direction, if you have a target to hit then you should optimize to hit that target, putting it in the center of all possible blast zones. No doubt that's how the rocket scatter is balanced.

Of course, the origin of this deviation that irks you is that, since scatter is based on a series of accuracy rolls, the chance to hit in abt particular tile forms a bell curve, with pinpoint in the edge.

(Then again playing with the grenade tossing rifles in ME:A I realized that there too sending the shot right at the reticle is the last likely outcome)

[hewhoispale]

* the quirk being that, sometimes, some tiles away from the centre are each more likely to be hit than the one aimed for.

I don't think this is really that strange, ultimately. If you take, say, a 30% shot with a soldier's gun, you're going to miss more than twice as often as you hit, so why not with a low chance rocket?

Not my point, it's more subtle:

1) Yes, it is more likely and should be more likely that the rocket should miss than hit the tile aimed for.
2) Further it is reasonable that the total chance of scattering any given distance (added up(/integrated) over every different possible scatter direction) can be larger than a zero scatter.
3) What seems odd is that the chance of scattering a non-zero distance in an individual direction can be higher than the chance of zero scatter.

(3) implies that the soldier has a very odd sort of 'bad aim' where arbitrary tiles which aren't the one aimed for will each be more likely than the one aimed for. Bad aim would be more intuitively modeled instead (I believe at least) where the variance of the shot increases while the profile of the shot distribution remains qualitatively similar (i.e. if it were a normal distribution for high aim then it is a normal distribution but with higher variance for low aim - not a different distribution entirely which is what we appear to generate here).

(and again not railing here for it to change as ultimately it achieves the most important objective of implementing rocket scatter and thus not just a 'I click this button and everything dies' weapon)

I can appreciate the math here in regards to the sort of oddity of an 80% rocket is more likely to hit next to the target that hitting the target. A question though: as XCOM2 is not a Phoenix Command-esque hard simulation, does the current math generate a reasonable verisimilitude of deviation? The current method is seems like it is pretty low-impact in terms of on the fly accuracy calculations, and I think we can all agree that efficient math is important for the current state of the game engine. The rocket scatter calculation actually reminds me a lot of tabletop games, like the ball scatter in Blood Bowl.

[Blackadder]

Took me a while to get where you're going. Basically, scatter 0 should have a higher chance than scatter 1, which should have higher chance than scatter 2, which is higher than scatter 3, which is higher than scatter 4, however, scatter > 0 has a higher chance than scatter zero. That does make sense.
However, you also need to notice that the chance to actually hit the tile you target in the blast in, in fact, always 100%. With a blast radius of 6, only hitting the absolute max scatter of 6 in the correct diagonal will make it not hit the tile.
So wielding a weapon that will randomly scatter in any given direction, if you have a target to hit then you should optimize to hit that target, putting it in the center of all possible blast zones. No doubt that's how the rocket scatter is balanced.

Of course, the origin of this deviation that irks you is that, since scatter is based on a series of accuracy rolls, the chance to hit in abt particular tile forms a bell curve, with pinpoint in the edge.

(Then again playing with the grenade tossing rifles in ME:A I realized that there too sending the shot right at the reticle is the last likely outcome)

Not quite, it seems reasonable for the total chance of any scatter one (any direction) being higher than a scatter of none. What seems counter intuitive/quirky is that the chance of scattering one tile to the left (or to the right or up or down individually) can have a higher chance than scatter 0. Yeah I can see the appeal of the current system - very concise code wise (I imagine) and simple to understand even if all the ramifications are not (and I wouldn't say I'm irked by it, merely curious ).

I can appreciate the math here in regards to the sort of oddity of an 80% rocket is more likely to hit next to the target that hitting the target. A question though: as XCOM2 is not a Phoenix Command-esque hard simulation, does the current math generate a reasonable verisimilitude of deviation? The current method is seems like it is pretty low-impact in terms of on the fly accuracy calculations, and I think we can all agree that efficient math is important for the current state of the game engine. The rocket scatter calculation actually reminds me a lot of tabletop games, like the ball scatter in Blood Bowl.

Yes, hence my general comments to that effect. I was more curious as to whether this quirk was intentional (and if so why) rather than saying Xcom needs something better than this. The mechanic as is seems to do a 'good enough' job of modelling scatter.

[Jadiel]

True, but if I found that the best way to maximise the probability of hitting a head shot was to point at the targets feet, I'd ask for a different gun...

That comparison is overlooking two key facts about rockets

• They scatter in a random direction
• They have an AoE

The result is that even when it's more likely your shot will end up two tiles away from the targeted tile (bad aim, no FitH), you're still better targeting directly the tile you want to hit because it maximizes the chance that tile will still be in the AoE. If you were to target a tile that's 2 tiles to the left of your target because the best probability is to hit two tiles away, you are as likely to have your rocket move further left and finally hit a tile that's 4 tiles away from the one you wanted to hit.

To use your comparison, maybe you have a slightly better chance of hitting a head shot if you target the feet, but you are also much more likely to totally miss your target (or even sometimes to hit your friend), whereas if you were targeting the head you might hit the chest or an arm instead (which is still better than not hitting at all).

You're putting words in my mouth. I never said that the current system incentivises you to shoot anywhere other than the target you wish to hit.

I was just trying to make the point that a gun which is systematically biased to hit a point or points other than where you are aiming is broken. If I'm aiming at a particular point, that should be the most probable destination of my bullet. The probability of hitting that point could be 100% or 10% or 1%, but if that's where I'm aiming, I should be more likely to hit that point than any other. Otherwise the gun is broken.

[LordYanaek]

You're putting words in my mouth. I never said that the current system incentivises you to shoot anywhere other than the target you wish to hit.

I was just trying to make the point that a gun which is systematically biased to hit a point or points other than where you are aiming is broken. If I'm aiming at a particular point, that should be the most probable destination of my bullet. The probability of hitting that point could be 100% or 10% or 1%, but if that's where I'm aiming, I should be more likely to hit that point than any other. Otherwise the gun is broken.

Well, actually your chance to hit the point you are aiming with a rocket is 100%.
It might not be the center of the AoE but it will always be in the AoE.
As for not saying the current system incentivises you to shoot away from the target, how do you understand this (bold is mine)

True, but if I found that the best way to maximise the probability of hitting a head shot was to point at the targets feet, I'd ask for a different gun...

[Jadiel]

Well, actually your chance to hit the point you are aiming with a rocket is 100%.
It might not be the center of the AoE but it will always be in the AoE.

True, but my chance of hitting all the targets that were highlighted in the preview is certainly not 100%.

As for not saying the current system incentivises you to shoot away from the target, how do you understand this (bold is mine)

True, but if I found that the best way to maximise the probability of hitting a head shot was to point at the targets feet, I'd ask for a different gun...

The point I was trying to reiterate (it's the same one made in the OP) hasn't changed since I wrote the post. When you choose a target, it seems reasonable to assume that your shot is more likely to hit that point than any other. If I was shooting a gun where that wasn't the case, I would say that the gun was broken.

I have never said anything about the way you should or should not play the game based on this (possibly broken) mechanic.

[Tuhalu]

3) What seems odd is that the chance of scattering a non-zero distance in an individual direction can be higher than the chance of zero scatter.

(3) implies that the soldier has a very odd sort of 'bad aim' where arbitrary tiles which aren't the one aimed for will each be more likely than the one aimed for. Bad aim would be more intuitively modeled instead (I believe at least) where the variance of the shot increases while the profile of the shot distribution remains qualitatively similar (i.e. if it were a normal distribution for high aim then it is a normal distribution but with higher variance for low aim - not a different distribution entirely which is what we appear to generate here).

(and again not railing here for it to change as ultimately it achieves the most important objective of implementing rocket scatter and thus not just a 'I click this button and everything dies' weapon)

Because of the way the new rocket position is calculated, the center tile is actually still the most likely to be hit, outside of exceptionally bad aim circumstances (eg. 20 aim after modifiers). This is because both the distance and the direction is randomized. While it's more probable for the rocket to scatter a certain distance than it is to not scatter, it's less likely for it to scatter onto any other single tile than it is to not scatter at all.

[LordYanaek]

True, but my chance of hitting all the targets that were highlighted in the preview is certainly not 100%.

When you take a regular shot, you chance to hit is rarely 100% either.
This point also goes the same way as my own #1 tip to use rocketeers efficiently

The first trick is to mentally reduce the displayed AoE so you don't consider you'll hit everything. If you do, great, it was a lucky shot but i don't rely on it more than i would have relied on a direct kill from a vanilla repeater. Once you do this you'll learn to appreciate how much cover you can reliably blow and plan on this rather than try to include as many enemies as possible in the AoE.

The point I was trying to reiterate (it's the same one made in the OP) hasn't changed since I wrote the post. When you choose a target, it seems reasonable to assume that your shot is more likely to hit that point than any other. If I was shooting a gun where that wasn't the case, I would say that the gun was broken.

I have never said anything about the way you should or should not play the game based on this (possibly broken) mechanic.

OK, let's stop the discussion around aiming for the feet in order to hit the head.

Most of the issues in this thread come from the "default" values on JoINrbs spreadsheet being totally irrealistic for a rocketeer. Those are the stats of a squaddie tech trying to fire his rocket at long range. If you consider something slightly more realistic such a LCpl rocketeer with FitH and 69 aim (base 65, i wouldn't go lower for a rocketeer) you're looking at 13% chance to center the AoE on the exact targeted tile with each tile directly orthogonal from that one having 7.6%. The chance to hit the targeted tile or a tile directly adjacent is 59%. It's already much more reliable for a very long range (20 tiles) rocket.
Firing after a move is only an option if you have around 100 base aim (that would be 75 start aim MSgt rocketeer with an aim PCS). In this case you can shoot up to 17 tiles and still have higher chance to center your AoE on the targeted tile than any other specific tile but that chance is only 4.5%. In this case you have about 62% chance to land the rocket within 2 tiles of the targeted point. It's not great for a MSgt but the rocket launcher isn't made to fire after a move in LW2.

The issue with high scatter is not that the gun is broken, it's the soldier is bad. If your guy can't aim, you can give him the best gun possible, it's unlikely he will land a hit. The rocket launcher is simply harder to aim than a regular gun.

[DonCrabio]

Today I fired my rocket ~15 tiles to center mass of not activated 4 man squad and it missed all targeted things completely. I was not moving before shot, my Technical have around 70 AIM and FitH perk. It was T2 gauntlet, if it matters.

This is insanely unreliable ability as it is now.

[JulianSkies]

Today I fired my rocket ~15 tiles to center mass of not activated 4 man squad and it missed all targeted things completely. I was not moving before shot, my Technical have around 70 AIM and FitH perk. It was T2 gauntlet, if it matters.

This is insanely unreliable ability as it is now.

You... 100% did not, at all, under any circumstance, do that. Because it is impossible.
Because with Fire in the Hole the maximum scatter is 2 if you don't move. For you to hit absolutely nothing... I can't even fathom a configuration for those four enemies to be in so that it'd miss. Maybe if you were aiming so that only the two farthest tiles of the AoE were targetting them, maybe, then a scatter of 2 would have whiffed, but you said center mass, so no matter how close or how scattered they were there was no way that'd have happened since with an AoE of 6 there's no way that there wouldn't be at least something within four tiles of the central tile for you to hit.

[DonCrabio]

Today I fired my rocket ~15 tiles to center mass of not activated 4 man squad and it missed all targeted things completely. I was not moving before shot, my Technical have around 70 AIM and FitH perk. It was T2 gauntlet, if it matters.

This is insanely unreliable ability as it is now.

You... 100% did not, at all, under any circumstance, do that. Because it is impossible.
Because with Fire in the Hole the maximum scatter is 2 if you don't move. For you to hit absolutely nothing... I can't even fathom a configuration for those four enemies to be in so that it'd miss. Maybe if you were aiming so that only the two farthest tiles of the AoE were targetting them, maybe, then a scatter of 2 would have whiffed, but you said center mass, so no matter how close or how scattered they were there was no way that'd have happened since with an AoE of 6 there's no way that there wouldn't be at least something within four tiles of the central tile for you to hit.

Well, I don't make video capture of my gaming, so don't have a proof to show. But, it was just as I said. Maybe there was 16 or even 17 tiles to the target square, but all other was exactly as I wrote before. Yes, definitely, no more than 17, because my 15 speed assault was next to Technical and he was able to RnG and kill farther guy after activation. Initially enemies was in a tight formation, probably it was possible to hit em all with regular HE grenade from my Shinobi.

Interesting, if I have hard save and try to replicate the issue on another computer, will it behave the same?

[Zyrrashijn]

Today I fired my rocket ~15 tiles to center mass of not activated 4 man squad and it missed all targeted things completely. I was not moving before shot, my Technical have around 70 AIM and FitH perk. It was T2 gauntlet, if it matters.

This is insanely unreliable ability as it is now.

Did you do anything before the shot? That would count like a move.

[Tuhalu]

To reiterate. The way the game is coded, it doesn't actually care if you moved before firing or not. It just cares if you have only 1 action point left when firing. So any single action taken before firing will reduce your accuracy and increase your maximum scatter, unless you use a Command to give him back the action point.

[DonCrabio]

Today I fired my rocket ~15 tiles to center mass of not activated 4 man squad and it missed all targeted things completely. I was not moving before shot, my Technical have around 70 AIM and FitH perk. It was T2 gauntlet, if it matters.

This is insanely unreliable ability as it is now.

Did you do anything before the shot? That would count like a move.

Nope. I had no actions spent before the shot. I have habit to make quick saves before such shots, maybe it still there, I will check this in the evening.

[Zyrrashijn]

Well, if you have, a screenie of the situation would be helpful to get what's going on.

[DonCrabio]

It was funny situation. After reading this topic, about scatter values and all this stuff I was pretty optimistic about this shot

Even if I don't have hard save, I will try to replicate this issue, not a big deal, since I have Technical in every squad.

[Blackadder]

Because of the way the new rocket position is calculated, the center tile is actually still the most likely to be hit, outside of exceptionally bad aim circumstances (eg. 20 aim after modifiers). This is because both the distance and the direction is randomized. While it's more probable for the rocket to scatter a certain distance than it is to not scatter, it's less likely for it to scatter onto any other single tile than it is to not scatter at all.

You make a good point (gameplay wise) that the central tile is still probably the most likely tile to be hit by some part of the AoE in all cases. I think the actual aiming of the rocket (what tile it physically explodes on) is still slightly quirky with this mechanism.

One thing I hadn't considered that this mechanism may be modelling (or alternatively another way to rationalise the existing mechanic) is the randomness of shrapnel/explosion scatter from the detonation tile. That is, the rocket is 'in real life' (great term for turn based gaming ) most likely to detonate on the central tile (even if it doesn't animate that way) but the effects of the explosion will on average not be centred there. Modelling/rationalisations can always be made complicated it seems.

[LordYanaek]

One thing I hadn't considered that this mechanism may be modelling (or alternatively another way to rationalise the existing mechanic) is the randomness of shrapnel/explosion scatter from the detonation tile. That is, the rocket is 'in real life' (great term for turn based gaming ) most likely to detonate on the central tile (even if it doesn't animate that way) but the effects of the explosion will on average not be centred there. Modelling/rationalisations can always be made complicated it seems.

Yep, but more importantly, modelling/rationalisations can always be fitted to what you see in game as it is a an abstraction anyway.
I like your idea, hope you don't mind if i steal it for my own use

[Blackadder]

Yep, but more importantly, modelling/rationalisations can always be fitted to what you see in game as it is a an abstraction anyway.
I like your idea, hope you don't mind if i steal it for my own use

I'm not sure how I'd even claim IP on this so...yeah, have at it

[Manifest]

If I'm throwing a dart at a dartboard and aiming for the bullseye then, in the absence of biased throwing, the bullseye is the most likely spot for my dart to land of all the individual spots it could land (even if I'm lousy at darts). This isn't to say that it is more likely I get no scatter than some scatter. Indeed, I find it very reasonable that the amount of scatter would have a peak in it's probability distribution at some non-zero number. But this only says that it is more likely that the dart lands at a non-zero distance from the bullseye, not that it is more likely that the dart lands at that distance and in a specified direction from the bullseye.

Just thought this may be an interesting discussion (and I may be totally wrong in which case...let me know).

Cheers

Are you sure that this is the case in real life? I believe that if you throw ten darts the average position of all the darts is always more likely to be closer to bullseye, but that does not necessarily mean that any individual dart is most likely to hit bullseye than any other point. I'm not actually sure that'd be the case.

[Blackadder]

Are you sure that this is the case in real life? I believe that if you throw ten darts the average position of all the darts is always more likely to be closer to bullseye, but that does not necessarily mean that any individual dart is most likely to hit bullseye than any other point. I'm not actually sure that'd be the case.

In the absence of bias in your throwing action then I think so. Assuming that the reason you miss where you are aiming is down to various (assumed independent, possibly falsely(?)) random factors (muscle twitches, misjudgment, distraction, air currents etc.) then the combined effects of all of these adjustments to the landing point would just as likely cancel out rather than superpose to cause a larger deviation. Adding this up for all the possible scatter directions leads to more chance of a direct hit while the chances of larger deviation are spread across the larger area that they cover.

Put another way, I think the mechanic in use here does a roll of the dice to decide each number of tiles scatter but I think only one roll to decide scatter direction. In the above reasoning it may be better modeled as each roll having a random scatter (i.e. rolling two lot's successful scatter may in fact cancel out). But again this is nitpicking.

[DonCrabio]

It's a shame! I don't have relevant save file and I must admit, I wasn't able to replicate this issue in another missions. Probably it was a bug. But there is some positives, as result of my investigation my rocket launches become more successful and now have solid place in my tactics.

P.S. I still think what flamer Technical mush more useful in current state of the game, because of crowd control. And someone can enlighten me, what the point of concussion rocket?