Net lag, and how it distorts reality.

[Rickenbacker]

I've had some discussions about this in the MA recently, and many people don't seem to realize that there is such a thing as lag even if you have a perfect 100ms ping, nor how it affects you in the game.

When you're flying AH your FE presents you with a view of where everything is that's different (sometimes wildly so) than _everyone_ elses. This is mainly due to net lag, as the FE gets your control input, sends an update to the server, that is then sent out to everyone within visual view of you. This means that even if you have a  steady 100ms lag, and the other person does as well (which would be very good indeed, and probably never happens) the other person sees you where you were 0.2 seconds ago. If someone has a crappy connect, this increases, and half a second to one second lag is probably the norm. That means that you always see where everyone around you were _half_a_second_ago_, and vice versa.

So where does this leave us when it comes to gunnery and collisions? For gunnery it means that if you're shooting at someone else, he'll see you shooting behind him, i.e. where his plane was half a second ago, but that's where it shows on your FE. If you hit him, your FE sends that message to the server, which sends it to him FE and he hears the ping 1/2 a second _after_ you see the hit flashes. If you're in a headon this means that you'll almost always recieve the damage after the other guy passes you (and I've seen lots of "cheater" and "warper" cries when this happens, some people even relog even though this is perfectly normal).

For collisions this means that you can never really "ram" anyone in the game. Sure, you could try to get in front of someone else, and hope that he runs into your plane on his FE, or you could go for his nose in a headon pass, but this is a dicey tactic, that can't really be described as a "ram" IMO. The enemy can also easily avoid dying by simply pulling away from you and not hitting you. From behind it's entirely impossible to kill someone with a ram, as he's several hundred yards further ahead on his FE, so if you hit his tail you'll die (your FE sees a collision) while he'll live (his FE sees you blow up 100 yards behind or more). If you avoid the collision you'll live, everytime. If you don't, it's your own fault, since they other guy really couldn't know that you were about to collide with him (since he sees you somewhere else than you do).

This also makes a significant difference in tail chase situations, since you both see each other maybe 1/2 second _behind_ where you are on your own FE, the pursuer sees the fleeing plane closer, and the fleeing plane sees the pursuer further away. This error increases with speed (as you travel further in that 1/2 second) so that in high speed chases errors of up to 500 yards aren't uncommon. This accounts for many of those "Cheater, you killed me at 1200 yards!" cries.

I hope this was useful for someone, I see a lot of people in the arenas misunderstanding, or plain not knowing about, how net lag works in an online flight sim. I might have been rambling a bit, but I'm a little tired of all the unneccessary "cheater" calls on channel 1.

See you all up,


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        Rickenbacker (Ricken)

                -ISAF-
the Independent Swedish Air Force

[funked]

Well said Ricken.

Hoof of WB and WW2OL wrote some great stuff on net lag effects that still applies to AH: http://www.rdrop.com/users/hoofj/netlag.htm

Many so-called "FM bugs" in AH can are caused by the effects Hoof explains.  

But people are more interested in griping than expanding their understanding of how the net affects their perception of enemy aircraft performance.  

[Rickenbacker]

Yup, that's an excellent article, just couldn't find the link, so I wrote my own. Everyone should read that, though, as it goes into a lot more detail and explains quite a few oddities.

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        Rickenbacker (Ricken)

                -ISAF-
the Independent Swedish Air Force

[LLv34_Snefens]

 

Originally posted by Rickenbacker:
For collisions this means that you can never really "ram" anyone in the game. Sure, you could try to get in front of someone else, and hope that he runs into your plane on his FE [...] If you avoid the collision you'll live, everytime. If you don't, it's your own fault, since they other guy really couldn't know that you were about to collide with him (since he sees you somewhere else than you do).

Unfortunately the fact that we have a "only collide if YOU see it" model, means some  deliberetly go just in front of you plane trying to force your death and not theirs. That the lag is unknown only means that it won't succeed every time (not knowing how much they need to lead). It really isn't always your fault (thinking about bombers here)

Well just my opinion. I know both collision models have its flaws, but having tried both I just prefer the "mutal collision model". You just need to learn that you shouldn't fly just in front of the enemy, for TWO reasons now. Pretty simple.

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Ltn. Snefens
RO, Lentolaivue 34
My own homepage

[funked]

Snefens think about it some more.

With a "mutual" collision model, I could intentionally ram you, and you would die.
However on your FE, due to net lag, you would not see me colliding with you!  But you would die regardless.

So intentional ramming would become very easy.
And people would be constantly dying from "collisions" which were not visible on their end.

I would quit if that were implemented, and I would not be alone.

[This message has been edited by funked (edited 11-15-2000).]

[LLv34_Snefens]

Like I said, there are flaws about both of them and I am well aware that someone might find it funny to try to ram into you, but they will go down too then. I know that won't discourage all from trying, but most.
But, with the current model there are also people going for the ram, only they can get away from it alive.

Then there are the accidental collisions. I hate being the only one going down. It just doesn't feel right.

About not seeing a collsion I consider it much the same we have with our gunnery. There you rarely see the tracers pass just by you (in deflections), but you have a pretty good idea if he is close to hitting you with his bullets anyway.
If people can learn to accept the gunnery being lagged on their FE like Rickenbacker describes, I don't see why they can't accept mutual collisions too.

A can of worms I know. Just how I would like it to be. Oh well.

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Ltn. Snefens
RO, Lentolaivue 34
My own homepage

[This message has been edited by LLv34_Snefens (edited 11-15-2000).]

[Maniac]

In all these years i have never worried or spent an tought on net lag (warps is another story).

My philosophy is "shoot the target in front of you" and it seems to work djust fine so far hehe.

I always fly my AC in regards to what the con is doing on _MY_ FE and i never ever worried about how it might look on his FE....

Regards



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AH : Maniac
WB : -nr-1-

[Rickenbacker]

Well Snefens, the problem I have with mutual collisions is that it disturbs my sense of "fairness", if you will  . It means that even if you do all you can to avoid a HO collision, pull up at 500 yards and whatnot, you die _anyway_ because some dweeb couldn't be bothered to do so.

We don't have mutual collisions for the same reason we have killshooter, to keep morons from ruining the game for others. Ideally I'd like to see killshooter removed too, but I know that there's no way in hell it would work.

Hope I didn't come off to abrasive there, I would like to see "real" collisions, but with net lag being a fact of online life, the "FE-determined" collision model is the only one that's somewhat fair.

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        Rickenbacker (Ricken)

                -ISAF-
the Independent Swedish Air Force