Webs posted 12-06-98 02:53 PM ET (US)        

Because of Net lag, a plane's position can appear in a different place on each FE. It's almost as hard as general relativity to understand (and rather similar, I might add), but let me try to explain with examples.

Assume you have Net lag of 200 ms to the iMoL server. Assume the Net lag of the pilot you're fighting is also 200 ms.

Let's use the iMOL server (the host) as a common frame of reference. It takes 200 ms for the data from each player's FE to get the the host, which therefore interprets each plane's position 200 ms in the past. When it gets the data for your planes position, another 200 ms has passed and you have flown on. Let's assume the host is a stationary, imaginary, third point in space exactly between you two.

Now, the host has to then send this information to the other player. This takes another 200 ms.

The result is that the other player's FE displays your plane where it was 400 ms ago on your own FE. And your FE displays his plane where it was on his FE 400 ms ago. You are both essentially fighting "ghosts".

Now for the examples.

1) Head-on.

You two fly in a game of head-on game of chicken, but neither pilot fires guns. You get to d2 away from each other. Let's assume it takes 800 ms to travel 100 yards, or d1 (roughly 250 IAS).

*What the host sees: The host sees you two at d2, but separated in space/time (bear with me, remember d1=800 ms) equally. In other words, if the host were a stationary, imaginary, third point in space exactly between you two, it would see you d1 to one side and the enemy d1 to the other (obviously).

*What you see: You see yourself 200 ms closer to the host point (which is d0.25), so to you it looks like the host point is only d0.75 away. However, you see the enemy 200 ms further in the past than the host does, which means you see it d0.25 farther away. The Net result is that you also see a distance of d2 between the two planes, but the host point is only d0.75 away from you.

*What the enemy sees: He sees exactly what you see. To him it looks like the host is closer to him.

Note that all frames of reference agree that the two planes are separated by the same distance.

At d1 from the enemy plane, you lose your nerve and (instantaneously) pull up out of his way. He continues to fly straight.

*What the host sees: The host, in its own frame of reference still at the midpoint between the two planes (d0.5 from each), sees you pull up 200 ms later, or when you get to d0.25 away from it. In the meantime, the other plane travels another d0.25. In other words, the host sees you miss by d0.5.

*What you see: You pull up at d1. Clearly you pass above the enemy.

*What the enemy sees: The enemy's FE will get the message that you pulled up 400 ms after you actually do. During those 400 ms (d0.5), you appear to be flying straight. He also continues to fly straight for d0.5. The result, is that on his FE the two planes have collided.

This argues against the one collision, two-pilot death modification

iMOL and most players agree. If you hit another plane, you suffer the consequences, but if the other guy doesn't collide on his FE, he doesn't pay a penalty.

OK, let's examine a tailchase. Again, assume you both have Net lag of 200 ms to the iMOL server. It takes 200 ms for the data from each player's FE to get the the host, which therefore interprets each plane's position 200 ms in the past. When it gets the data for your planes position, another 200 ms has passed and you have flown on.

Example: You on a slower enemy's 6.

You are following your opponent headed south to north. You are going twice as fast as him. Let's assume it takes 400 ms for you to travel d1 and 800 ms for him to travel d1. You reach a point where the host sees you d1 from the enemy in front of you. Let's place the imaginary, motionless host point midway between the planes in its own frame of reference.

*What the host sees: The host sees the enemy plane d0.5 to the north and it sees you d0.5 to the south. Both planes head north, at different speeds.

*What you see: You see yourself 200 ms closer to the host point than it sees you. Since you travel d0.5 in 200 ms, you see that point d0.5 closer to you than it sees you - you see the host point at exactly your own position. You see the the enemy plane 200 ms slower than it appears to the host. So it appears to you that the plane is another 200 ms in the past. The enemy travels d0.25 in 200 ms, so it appears that much closer to you in your frame of reference than it does to the host. He is d0.5 from the host in the host's frame of reference, and the host is where you are in your frame, so that means the enemy appears only d0.25 in front of you. Time to kill him.

*What the enemy sees: On his own FE, he has spent another 200 ms traveling away from the host after the host saw him at d0.5. So he is another d0.25 away. To him, the host is d0.75 behind him. (Remember, you see the host - and yourself - only d0.25 behind him!). He sees you 200 ms farther in the past than the host, which is d0.5 worth of distance. So, he sees you another d0.5 back of the host in its own frame of reference, which is already another d0.25 farther behind him. He sees the host at d0.25 + d0.5 back, and you at d0.5 behind the host + a d0.5 time lag - in other words, he sees you at d1.75 back.

The difference is extraordinary. You see only d0.25 between the two planes. He sees d1.75 between them. This 150-yard difference holds for these speeds - which, frankly, are somewhat slow. the difference increases with higher speeds.

In the HO example, a d1 pull up suffices to avoid a collision in theory. In fact, a number of WB players get worse than 200 ms ping times, airframe momentum, and actual speed enters into it as well, but this is theory, so we can ignore facts.

Similarly, the discrepancy when following a plane changes with speed and lag (left as an exercise for the reader).

I really don't have the inclination to get into two- or three-dimensional problems, but, roughly, on his FE he saw you where you used to be, and you see him where he used to be, and you see yourselves where you are.

As an aside, unless you know the ping times and speeds of a plane, it is impossible to force a ram. You can guess, and get lucky once in a while, or zig zag at d2-d4 in front of enemies, but it's a non-issue, I think.

Webs, CO 101 "Red" Squadron, IDF

Dolfo posted 12-06-98 03:05 PM ET (US)            

Wow. You must be (so am I) one of those guys who can't watch "The Terminator" without getting irritated at how stupid the basic premise is (G)

Anyway, if you're basing your perception of

"where you are" on what you see, you really would't see where you are as where you are, because nothing you see would be where it is.

Hehehe... where's the aspirin?