Support #17343

SACLOS ATGMs do not work when frame rates are low

Added by maturin about 4 years ago. Updated about 3 years ago.

Status:Closed Start date:02/05/2011
Priority:Normal Due date:
Assignee:- % Done:

0%

Category:Config
Target version:-
Component:sys_missileguidance Affected Version:
Close Reason:

Description

ATGMs guided by the player moving their reticule have a habit of simply blowing up a few meters after they are launched. This seems to be because the script telling the missiles to follow the line of sight is delayed by poor performance. As a result, it is as if the rocket motor has failed.

One way to fix this would be to exempt these guided missiles from normal ballistics behavior, enabling them to fly with a flat trajectory unless overruled by a functioning guidance system. Alternately, you could make them climb a few meters after launch for some buffering altitude, giving a chance for a slower CPU to catch up. I don't think anyone would notice either slightly inauthentic workaround.

ACE seems to prize economy in its scripts, such as with the Hellfire system, so I don't think this an unwarranted request to make. Obviously this cannot be universally reproduced, unless you want to fill the map with hundreds of AI or overload your CPU with background programs, etc.

Latest ACE build, tested with the ATGM BRDM and Konkurs CSW.

History

Updated by jaynus about 4 years ago

I thought all rocket munitions used perFrame? not case?

Updated by maturin about 4 years ago

I wouldn't know. But SACLOS missiles are highly vulnerable to sagging into the ground. You're not going to have problems with AGMs, AA or dumb rockets.

Updated by Sickboy about 4 years ago

  • Status changed from New to Assigned
  • Assignee set to zGuba
  • Target version set to 1.9
  • Component set to sys_missileguidance

Updated by zGuba about 4 years ago

I am afraid that one cannot be improved further.

Updated by jaynus about 4 years ago

zGuba wrote:

I am afraid that one cannot be improved further.

So it does use the rest of guidance perFrame? k.

@maturin: The scripting mechanics we use for missiles is a per-frame script run. That means it gets run per-frame, regardless. This is to avoid script-lag (bad missions, etc). However, this makes critical operations bound to FPS performance.

Updated by maturin about 4 years ago

Hold on, don't close it yet. I understand that the guidance system has performance limitations that can't be helped. But instead of changing the guided performance of the missile, why not change its unguided ballistics?

You can fire a MANPAD without a lock and the missile will fly in a straight line, powered by its rocket motor and unaffected by gravity. ATGMs, meanwhile, have proper ballistics and plunge into the ground without guidance.

So I suggest making ATGM behave like MANPADs. If all goes well with the guidance system, they will behave like normal. But if your CPU is running too slow, the missile will fly in a straight line until the guidance kicks in. Since a player will be aiming at the target the whole time anyways, they will never notice that anything went wrong.

Updated by zGuba about 4 years ago

  • Category set to Config
  • Status changed from Assigned to Feedback
  • Assignee changed from zGuba to q1184

Might need q1184's expertise.

Updated by rocko about 4 years ago

  • Target version changed from 1.9 to 395

Updated by rocko about 4 years ago

  • Tracker changed from Bug to Support

Updated by rocko about 4 years ago

  • Target version deleted (395)

Updated by Nou almost 4 years ago

maturin wrote:

So I suggest making ATGM behave like MANPADs. If all goes well with the guidance system, they will behave like normal. But if your CPU is running too slow, the missile will fly in a straight line until the guidance kicks in. Since a player will be aiming at the target the whole time anyways, they will never notice that anything went wrong.

So the rockets will then continue to fly straight on forever then?

If your frame rate is that low someone is doing something wrong, either the mission maker or yourself (as in you didn't upgrade your computer to handle ArmA2).

Updated by maturin almost 4 years ago

You know quite well that many people have low framerates even with systems that meet the specs, and that many computers get decent framerates yet can have performance hit a wall when a mission goes over a certain number of AI or starts using complex scripts.

Updated by Sickboy almost 4 years ago

Scheduled scripts actually don't affect the FPS like in A1, they still can but generally due to the scheduling the fps isn't or isn't as much affected, depending on the executed statements.
Some ref http://ace.armastack.info/index.php/157/low-er-performance-when-running-with-ace
Non scheduled scripts like events or perframe still affect FPS as before.

PerFrame coding is in this case recommended as it pertains a precise and time sensitive operation, but this could further reduce FPS, while giving proper control back - unless the FPS is so dramatically low that things are uncontrollable obviously.

Updated by maturin almost 4 years ago

Just an update, Konkurs missiles are likely to sag into the ground just after launch when FPS is around 15. Even if you they do not fall out of the sky immediately, they are much less accurate, only changing direction from the guidance ever hundred meters or so. They look like Dragon ATGMs in real life, only worse, and will often miss the target. Invar ATGMs like to bounce side-to-side, and can end up looping around behind the target.

Updated by rocko about 3 years ago

  • Status changed from Feedback to Closed
  • Assignee deleted (q1184)

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