On the oddities and failures of Kill Zone/Covering Fire

Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

This should really be a bug report but I haven't caught the issue with a save game, so I'll ask here first --

-- How many are noticing issues with Kill Zone not working or behaving as expected? And, similarly for Covering Fire?

I'm convinced there's a subtle interaction with the skills and/or unit states that's preventing one or both from working properly.

On an Advent HQ last night I had pods of 8 (an M3 rainbow) + 4 in a Gunner Kill Zone. I opened with a flame ambush that lit or panicked 6 of the 8. The other pod of 4 was uncontrolled. I got 2 shots at the pod of 4, which was exactly as expected (one ran away and the MEC overwatched in place). However, I got ZERO shots at the original pod of 8. From that pod of 8, four actually scampered to cover (two were on fire, two were not). The rainbow pod of 8 was entirely visible and at close range to my gunner. I don't get it. All four of the scamperers couldn't have had Shadowstep...

I remember watching DerAva videos in 1.2 of and seeing how poorly a Gunner Kill Zone performed (i.e. never taking clearly open shots), and now I've seen the same thing in my first use in 1.4.

Further, I've had Covering Fire, randomly fail to respond to units in cover taking actions. My specialist failed to shoot at two Advent who were both flashbanged (she had ~30% non-overwatch shots and had an Adv/Elite hair trigger equipped).

I'm wondering if there's either an unintentional limit on reaction fire, or if there's an unexpected interaction with other unit states like burning or disoriented?

Unfortunately to catch these issues one needs to pre-save both the game and screenshots to show the kill zone setup, which I'll do next time.

What are other's experiences?
LordYanaek
Posts: 940
Joined: Mon Jan 23, 2017 1:34 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by LordYanaek »

I've had a couple of occasions where Kill Zone didn't trigger but each time enemies were pretty far away from the soldier and might simply have moved out of vision range with the first tile (in which case OW doesn't trigger, that's a way you can escape from ADVENT OW if you don't have other counters.

It should be mentioned that Kill Zone, originally a sniper perk shows an AoE far greater than the normal vision of anyone without squadsight but your soldiers won't shoot at someone out of their vision range.
Lyzak
Posts: 81
Joined: Thu May 18, 2017 5:01 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Lyzak »

I recall there being a bug where if you flamethrower-ambush a pod to break concealment and you panic the pod leader, the pod 'scampers' before the game registers that you broke concealment, and thus you don't get reaction fire on the pod because you're 'still concealed.' I also have this vague recollection that supposedly Pavonis bugfixed this in 1.3 but what you're describing sounds exactly like it soooo...

:?

EDIT:
Combing through the 1.3 and 1.4 changelogs (unless I missed it), I could not find the fix I thought I saw. Perhaps this is still a bug then...
Last edited by Lyzak on Mon Jun 12, 2017 8:50 pm, edited 1 time in total.
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

Lyzak wrote:I recall there being a bug where if you flamethrower-ambush a pod to break concealment and you panic the pod leader, the pods 'scampers' before the game registers that you broke concealment, and thus you don't get reaction fire on the pod because you're 'still concealed.' I also have this vague recollection that supposedly Pavonis bugfixed this in 1.3 but what you're describing sounds exactly like it soooo...
Thanks Lyzak. This is very possibly what happened. The pod leader was one of the six I hit with the flame thrower. Maybe one of the devs can comment on whether or not this needs a bug report.
DerAva
Posts: 94
Joined: Thu Jan 19, 2017 8:46 am

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by DerAva »

Alketi wrote: I remember watching DerAva videos in 1.2 of and seeing how poorly a Gunner Kill Zone performed (i.e. never taking clearly open shots), and now I've seen the same thing in my first use in 1.4.
Haven't yet unlocked Kill Zone in 1.3/1.4 but I'm not really sure I had too many issues with it in 1.2. I remember a mission where I screwed up by using a Ghost Grenade on a gunner and then wondering why Kill Zone wouldn't trigger any shots on the next activation, but that was obviously my own fault.

The Flamethrower issue mentioned above is most likely the reason here, but hard to say without actually seeing it in action.
Lyzak
Posts: 81
Joined: Thu May 18, 2017 5:01 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Lyzak »

Yeah, I suspect Kill Zone is a red herring and this is actually the bug regarding pod behavior when their pod leader is panicked in a concealment-breaking ambush. Any overwatch shot would have failed to go off.
DonCrabio
Posts: 90
Joined: Fri Mar 24, 2017 7:51 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by DonCrabio »

I can confirm Kill Zone failure on flamethrower activation. Had this effect at least twice in my last campaign.
Jacke
Posts: 623
Joined: Sat Jan 28, 2017 1:10 am

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Jacke »

Could this be due to activating 2 pods simultaneously? And the Kill Zone only gets shots at one of pods, whichever one activates "first"?
DerAva
Posts: 94
Joined: Thu Jan 19, 2017 8:46 am

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by DerAva »

Two pods is not the problem I'm pretty sure. Here's an example from 1.2 with a 2 pod activation. Panic from the Flamethrower seems more likely.
Franzy
Posts: 69
Joined: Thu Apr 06, 2017 9:05 am

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Franzy »

I can confirm bug with Covering Fire not working sometimes, when enemies just shoot. Usually happens when the said enemies are in windows and/or on higher ground. Probably connected with stepping out and breaking line of sight this way (bugged LoS yet again).
tracktwo
Long War Dev
Posts: 241
Joined: Sat Jan 07, 2017 7:43 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by tracktwo »

The panicked leader triggering the bug sounds like a likely culprit, but I'm not sure it's necessarily concealment related. The earlier bug that we fixed was way back in 1.1 (I think?) and was related to pod leaders scampering before concealment broke, so they didn't know where XCOM was and would flank themselves by choosing high cover that was exposed to your (still concealed) soldiers. That was an attempted fix for the other (still open) bug where the AI just stands around if an enemy happens to walk through or spawn on top of fire while you're concealed. No unit is permitted to scamper until the concealment break is complete, so if you are seeing the pod scamper concealment *should* already be broken. This should be a fairly easy thing for me to reproduce though and I will try to track it down.

RE: Covering Fire, there is some weirdness there. I know of one specific case where it will not fire, which is if a unit moves from a tile where you cannot see the unit to one where you can only see them because they are peeking around high cover, and then they shoot at you or perform some other action that would trigger CF. Covering fire will not proc because the game specifically disallows overwatch shots on a unit that has moved and which you can only see because of a peek around cover. I don't fully understand the rationale for that, but I suspect there are good reasons for it that apply to regular overwatch. One case I can perhaps think of is a unit climbing a ladder/pipe on the edge of a building: they aren't peeking around the corner, they're climbing, so overwatch shouldn't trigger on them from units that aren't flanking that wall. That's just a guess, though, it may be something completely different, but it is very much intentional. I didn't attempt a change there specifically for CF because we were close to release and was worried about introducing a pretty major bug without having enough time for the testers to kick the tires, but it's something I should look at again.
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

tracktwo wrote:The panicked leader triggering the bug sounds like a likely culprit ...
RE: Covering Fire, there is some weirdness there.
Thanks for looking into these tracktwo. I've been trying to pre-save games to catch the Covering Fire issues and will do the same the next time I'm going to execute a flamethrower/Kill Zone ambush.

For Covering Fire I specifically had a case (early game) where a Specialist failed to fire on two visible Advent who were both flashbanged and didn't move but just fired shots in place. My specialist didn't shoot at all. The Specialists regular shots were 30%+ and she had plenty of reaction fire buffs to prevent going below 0%, so I have no explanation. The Specialist was the only one in overwatch, had visibility on both enemies (and no other enemies), and they were both flashbanged. If I catch either of these situations again I'll certainly provide a save game to help.

Cheers.
tracktwo
Long War Dev
Posts: 241
Joined: Sat Jan 07, 2017 7:43 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by tracktwo »

Thanks, I'd appreciate the saves if you can get some. The way the game detects if a unit moved is a bit weird to explain, so if they had moved with their last action the previous turn it may still consider them as moved for the purposes of the peek check if they shoot with their first action the next turn, but that shouldn't be the case if you flashbanged them between the two turns. So it's possible this is something else entirely.
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

tracktwo wrote:Thanks, I'd appreciate the saves if you can get some. The way the game detects if a unit moved is a bit weird to explain, so if they had moved with their last action the previous turn it may still consider them as moved for the purposes of the peek check if they shoot with their first action the next turn, but that shouldn't be the case if you flashbanged them between the two turns. So it's possible this is something else entirely.
Well tracktwo, I had it all setup with Kill Zone and a rainbow-pod flamethrower ambush, but this time I went 0-for-8 on panics. Not sure what the odds were on that, but I should probably play the lottery, or maybe there's another issue... With no panics, the Kill Zone worked exactly as expected.

I have a save in case you're able to force a panic on the Elite Officer or re-seed the RNG. Otherwise I'll try again!

Raquel has the Kill Zone set up.
Elise is the Technical.

https://drive.google.com/open?id=0B0IGE ... HhvaTRxRFU
tracktwo
Long War Dev
Posts: 241
Joined: Sat Jan 07, 2017 7:43 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by tracktwo »

Thanks for the save! The \savescum console command will adjust the random seed so you can get different results after a reload, so I'll do that until I can get a panic.
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

Ah, I didn't know about the \savescum command. I'll try it out as well. I also have a save before the Kill Zone was set, in case you need to set the Kill Zone yourself. Cheers.
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

tracktwo wrote:Thanks for the save! The \savescum console command will adjust the random seed so you can get different results after a reload, so I'll do that until I can get a panic.
To save you time tracktwo I used the \savescum command I was able to find the right RNG to panic the Elite Officer, and the Kill Zone still worked as expected. Good news (I guess)!

The only other major difference between this setup and the time I saw it fail was that there were two pods in the Kill Zone when it failed to fire on the pod with a panic'd leader. If I see that setup take shape again I'll save the game in advance. Unless there's a console command to move the enemies(?), then I can play around with this save game and move another pod into view...
tracktwo
Long War Dev
Posts: 241
Joined: Sat Jan 07, 2017 7:43 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by tracktwo »

You can move aliens around, yes. \AiDebugAi to show info about each unit, including their object ID (its near the top of the unit, not the XGUnit_XX one). Use \TeleportUnitIDToCursor <id> to move a particular unit to the cursor.
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

tracktwo wrote:You can move aliens around, yes. \AiDebugAi to show info about each unit, including their object ID (its near the top of the unit, not the XGUnit_XX one). Use \TeleportUnitIDToCursor <id> to move a particular unit to the cursor.
Thanks tracktwo, I found the issue.

It wasn't panic'ing the group leader. I believe the panic issue is either a red-herring, or perhaps was fixed as someone thought.

The issue with Killzone failing to fire is that an enemy must (presumably) enter a Killzone tile. Thus, if an enemy is already on a Killzone tile BUT it's an edge tile, and that enemy subsequently runs out of the Killzone, then no shot will fire.

Perhaps some will argue this is standard overwatch behavior, however, the Killzone appears on-screen as an AOE effect, similar to the Flamethrower. So one would think a unit placed within the tiles would trigger the effect and not require an additional "buffer" tile.

I would surmise that this wasn't an (obvious) issue in vanilla XCOM2 because only Sharpshooters had killzone and using it at squadsight range often meant the cone would cover the entire screen, thus enemies were rarely if ever on one of the edge tiles.

Below is the layout showing the issue.

Two pods in a Killzone. If anyone in the yellow box runs South, out of the Killzone, then no shots will fire at them.

Thus, the player needs to be aware that an additional one box buffer is needed around all enemies at the edge. To me this isn't obvious behavior and results in the seemingly inexplicable failure of Killzone, as the post title indicated. In the example below no shots will fire on 5 of the 8 enemies in the rainbow pod if they run South to take cover, despite the Killzone appearing to cover all enemies.

Perhaps it's possible to check if an enemy, which hasn't yet been fired upon, moves from a Killzone tile to a non-Killzone tile, and then trigger the overwatch shot...

Here's the save game with the setup shown and also with RNG to flamethrower panic the Elite Officer. You can play with the Killzone tiles to see the issue and trigger the pods with any offensive action.
https://drive.google.com/open?id=0B0IGE ... XkxVjZyMGc

Cheers.

Image
Tuhalu
Posts: 433
Joined: Wed Feb 01, 2017 9:02 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Tuhalu »

That's actually the way all reaction fire works. The enemy has to move into a tile that is visible to the reaction fire source and then move again. Both sides benefit from this as you can use this 1 tile safety rule to move into nearby cover without getting shot.
Glacialis
Posts: 5
Joined: Tue Feb 16, 2016 12:24 am

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Glacialis »

If that's accurate Tuhalu, then the graphic on screen needs to be adjusted. I've been using Kill Zone over and over again on two new MSGT Rangers, and it hasn't triggered in six fights. Not once.
tracktwo
Long War Dev
Posts: 241
Joined: Sat Jan 07, 2017 7:43 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by tracktwo »

Thank you for the very detailed analysis & save game Alketi, this was very helpful and saved me a lot of time. I agree that killzone shouldn't be lying to you about which targets are affected, regardless of which direction they run. I'll see what i can do about fixing it.
Dwarfling
Posts: 524
Joined: Wed Jan 25, 2017 12:16 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Dwarfling »

That is very good to keep in mind. Thanks Alketi!
tracktwo
Long War Dev
Posts: 241
Joined: Sat Jan 07, 2017 7:43 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by tracktwo »

Some more thoughts on this:

It seems to me that one of the fundamental issues here is that the cone is highlighting both the tiles and the units. This is misleading, because killzone doesn't target units at all! Only the tiles matter, and as for regular overwatch, a unit needs to move through a tile within the cone to be considered a target, but it doesn't matter whether they started inside or outside the cone.

So the first and simplest option is possibly to not highlight any units within the cone, just paint the affected tiles, assuming I can get that to work. There is still the potential gotcha there that painting the tile a unit is on but not all the ones adjacent to it can still let that unit escape if they move to those tiles that aren't affected, but that's a relatively straightforward rule that's easy to understand and is consistent with regular overwatch. Even units within the cone may not be shot at if they only move a single tile into cover or move outside weapon range. The gotcha with highlighting the units is that it draws your attention to make sure all the units are painted, without really paying attention to the tiles.

Thoughts?
Alketi
Posts: 159
Joined: Sat Jan 28, 2017 3:11 pm

Re: On the oddities and failures of Kill Zone/Covering Fire

Post by Alketi »

Thanks for chasing the issue tracktwo. )

To me, the fundamental issue is that the game appears to be lying to the player. The description of the Killzone reads:
Take a reaction shot against any enemy that moves or attacks within a cone of fire.
However, the caveat that the movement must be within two Killzone tiles, and not one, is not obvious. I'm 99% sure this is vanilla behavior that was just coded this way, because the more I think about it the more I remember Sharpshooter killzone also mysteriously not working for enemies at the edge, but at the time I never knew why.

However it's more of an issue now because the Killzone is narrower at non-squadsight ranges, so enemies are more often at the edge.

To me, the "buffer-tile" caveat is a result of Firaxis' implementation being pushed onto the end user, rather than something that is innately understood from the graphics as they're presented.

So my vote is to fix it so any targets or tiles that are highlighted trigger a shot on movement or attack, just as the description states. One way to do (re: hack) this might be to add a row of invisible tiles to both edges...

If you'd like to gather more internal opinions here are the two raw images without any markups. If there are beta testers or other developers that you haven't yet told about this issue (keeping in mind these are the most knowledgeable people about the game), it would be interesting to poll them about the second image, to see if they volunteer that potentially 5 Advent could escape without triggering an overwatch shot. And then show them the first image and ask what they think again.
http://imgur.com/a/kjNq0

Also, I understand if this fixing this is something that the team decides is not worthwhile.
Post Reply