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XyZspineZyX
09-01-2003, 12:43 AM
Is it just me or is there some serious collision problems in FB?

Seems that many times only one aircraft takes damage (typically the slower one I think) when a collision occurs.

Just recently, I ran into the wing of a bandit while bnz'ing = was coming in too fast.

My wing busted off (p47) and the 109 wasn't even hurt. I was diving on bandit at 800khm, I don't see how any aircraft could sustain a hit like that.

I can tell many more examples of this.

I see it as a bug - I would think both aircraft would be heavily damaged at least

S!
609IAP_Recon

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XyZspineZyX
09-01-2003, 12:43 AM
Is it just me or is there some serious collision problems in FB?

Seems that many times only one aircraft takes damage (typically the slower one I think) when a collision occurs.

Just recently, I ran into the wing of a bandit while bnz'ing = was coming in too fast.

My wing busted off (p47) and the 109 wasn't even hurt. I was diving on bandit at 800khm, I don't see how any aircraft could sustain a hit like that.

I can tell many more examples of this.

I see it as a bug - I would think both aircraft would be heavily damaged at least

S!
609IAP_Recon

Forgotten Wars Virtual War
Forum: http://fogwar.luftwaffe.net/forums/index.php
Website: http://forgottenwars.dyndns.org
Visit 609IAP at http://takeoff.to/609IAP

http://www.leeboats.com/609/sig/609_recon3.jpg

Agnus Dei, Qui Tollis peccata mundi, Miserere nobis. Dona nobis pacem

XyZspineZyX
09-01-2003, 01:12 AM
Yes, no need to post specifics because it happens a lot. It's obvious both should be damaged yet like you said only one is damaged... Major bug. At least, you should avoid collisions regardless of bugs or not.. Of course, it's frustrating when online; the guy that hit you or vice versa should not be allowed to continue fighting... http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Stef

XyZspineZyX
09-01-2003, 01:34 AM
To summarize and repost from an explaination of the same thing that I made elsewhere:

Upon some review of the track files from tonight, I think I've figured out how I managed a few kills while I was being chased.

The short answer: Lag.

The longer answer:
It appears to sort of be like Warbirds.

The full explaination (as best I can, simplified and not completely technical):

The host is running a server. We're all running copies of the game that connect to the central (host's) server. Each of our clients is responsible for keeping track of our own little part of the world, damage done to our own plane, and reporting shots taken and trajectory of bullets and bombs.

Each client reports this to the central server, and the central server then updates everyone else in the game. When your client gets the data from the server, it compares it to your current "world state" and then acts appropriately. When it comes to damage done, it's all up to your client to determine if the bullet data it was given by the server means that you got hit. In other words, as far as I'm concerned it can look like I'm hitting you with everything I've got, but if there's enough lag, your machine might not agree and therefore I don't do any damage.

So what's this got to do with the odd kills tonight?

Well, all of this updating does take a little bit of time. Usually it's not much, but if there's any lag at all things really start to get slow (computer time-wise). Near as I can tell, this is just like the old Warbirds suicide attack from the rear situation.

You're chasing an aircraft, and you're both getting updated position data. As you close on the aircraft in front of you and decide to ram it, your system takes the last known position of the plane you're chasing, sees that your current position coincides with the other aircraft and then allocates damage to you accordingly (ie, you go BOOOM!).

The problem here is that the position your computer used for the other aircraft isn't quite real time. It's maybe 1/8 - 1/4 second in the past.

So your system sees you hit the plane in front, declares a collision, kills you and then reports the position of the impact back to the server. The server then sends all this data to the other clients, including the plane you rammed from behind.

The target's client is told that an impact and explosion occurred at X position, and so it checks it against its player's current position. Of course, during all of this time the target aircraft is still flying, and has been for the last 1/2 second or so. The computer checks and then sees that the impact occurred behind the current location of the target aircraft, and because of that, declares it a miss and does not allocate damage to the rammed aircraft.

Higher speeds just make this even worse, unless the overtaking/ramming aircraft is moving much faster than the target plane. If there's a bit of lag, and you have two aircraft moving at 350kts, and the second is overtaking the first by only 40kts or so, it's likely that any attempts to ram will result in the chasing aircraft's destruction while leaving the target unharmed.

When I replayed the .ntrks tonight where one player claimed he was over me and then lost his engine, and where another claimed I suddenly warped into his plane and blew him up (I was unharmed), I saw that they both got very close, but never actually came into contact with my aircraft from my machine's perspective.

Since each client appears to be responsible for determining damage for its own aircraft and player, it didn't matter to my computer that other player's machines thought we hit. My client saw it as nothing more than a near miss and therefore didn't apply any damage to my aircraft as a result.

So in summary, ramming attacks from the rear are dicey at best. From head on or other aspects, they're far more likely to work.

IL-2/FB overall seems to have very good netcode and prediction. Most times even with 4 or 5 people playing it's just as smooth as it is on a local LAN. However, once the connection starts going a little south some weird things can happen. If you've ever noticed that sometimes in head on passes the planes will flash by, and then a half second later both explode (delayed impact), you've seen this kind of lag in action.

Unfortunately there's not a whole lot to be done about it, so far as I know. You just have to be aware of the limitation and know that getting extremely close to your target carries a significant risk of collision due to a momentary warp. Get no closer than about .15 and you'll probably be okay.

XyZspineZyX
09-01-2003, 04:41 AM
Recon_609IAP wrote:
- Is it just me or is there some serious collision
- problems in FB?
-
- Seems that many times only one aircraft takes damage
- (typically the slower one I think) when a collision
- occurs.
-
- Just recently, I ran into the wing of a bandit while
- bnz'ing = was coming in too fast.
-
- My wing busted off (p47) and the 109 wasn't even
- hurt. I was diving on bandit at 800khm, I don't see
- how any aircraft could sustain a hit like that.
-
- I can tell many more examples of this.
-
- I see it as a bug - I would think both aircraft
- would be heavily damaged at least

Totally agree. Every time I crash into a plane, the plane that i've crashed can bail out, but I can't! Every time I crash into a plane, my plane always explode before the "victim" explode! So unfair!

XyZspineZyX
09-01-2003, 07:23 AM
dito Recon!

XyZspineZyX
09-01-2003, 03:04 PM
Nice analysis, Binary!

BinaryFalcon wrote:
- To summarize and repost from an explaination of the
- same thing that I made elsewhere:
-
- Upon some review of the track files from tonight, I
- think I've figured out how I managed a few kills
- while I was being chased.
-
- The short answer: Lag.
-
- The longer answer:
- It appears to sort of be like Warbirds.
-
- The full explaination (as best I can, simplified and
- not completely technical):
-
- The host is running a server. We're all running
- copies of the game that connect to the central
- (host's) server. Each of our clients is responsible
- for keeping track of our own little part of the
- world, damage done to our own plane, and reporting
- shots taken and trajectory of bullets and bombs.
-
- Each client reports this to the central server, and
- the central server then updates everyone else in the
- game. When your client gets the data from the
- server, it compares it to your current "world state"
- and then acts appropriately. When it comes to damage
- done, it's all up to your client to determine if the
- bullet data it was given by the server means that
- you got hit. In other words, as far as I'm concerned
- it can look like I'm hitting you with everything
- I've got, but if there's enough lag, your machine
- might not agree and therefore I don't do any damage.
-
- So what's this got to do with the odd kills tonight?
-
- Well, all of this updating does take a little bit of
- time. Usually it's not much, but if there's any lag
- at all things really start to get slow (computer
- time-wise). Near as I can tell, this is just like
- the old Warbirds suicide attack from the rear
- situation.
-
- You're chasing an aircraft, and you're both getting
- updated position data. As you close on the aircraft
- in front of you and decide to ram it, your system
- takes the last known position of the plane you're
- chasing, sees that your current position coincides
- with the other aircraft and then allocates damage to
- you accordingly (ie, you go BOOOM!).
-
- The problem here is that the position your computer
- used for the other aircraft isn't quite real
- time. It's maybe 1/8 - 1/4 second in the past.
-
- So your system sees you hit the plane in front,
- declares a collision, kills you and then reports the
- position of the impact back to the server. The
- server then sends all this data to the other
- clients, including the plane you rammed from behind.
-
- The target's client is told that an impact and
- explosion occurred at X position, and so it checks
- it against its player's current position. Of course,
- during all of this time the target aircraft is still
- flying, and has been for the last 1/2 second or so.
- The computer checks and then sees that the impact
- occurred behind the current location of the target
- aircraft, and because of that, declares it a miss
- and does not allocate damage to the rammed aircraft.
-
- Higher speeds just make this even worse, unless the
- overtaking/ramming aircraft is moving much faster
- than the target plane. If there's a bit of lag, and
- you have two aircraft moving at 350kts, and the
- second is overtaking the first by only 40kts or so,
- it's likely that any attempts to ram will result in
- the chasing aircraft's destruction while leaving the
- target unharmed.
-
- When I replayed the .ntrks tonight where one player
- claimed he was over me and then lost his engine, and
- where another claimed I suddenly warped into his
- plane and blew him up (I was unharmed), I saw that
- they both got very close, but never actually came
- into contact with my aircraft from my machine's
- perspective.
-
- Since each client appears to be responsible for
- determining damage for its own aircraft and player,
- it didn't matter to my computer that other player's
- machines thought we hit. My client saw it as nothing
- more than a near miss and therefore didn't apply any
- damage to my aircraft as a result.
-
- So in summary, ramming attacks from the rear are
- dicey at best. From head on or other aspects,
- they're far more likely to work.
-
- IL-2/FB overall seems to have very good netcode and
- prediction. Most times even with 4 or 5 people
- playing it's just as smooth as it is on a local LAN.
- However, once the connection starts going a little
- south some weird things can happen. If you've ever
- noticed that sometimes in head on passes the planes
- will flash by, and then a half second later both
- explode (delayed impact), you've seen this kind of
- lag in action.
-
- Unfortunately there's not a whole lot to be done
- about it, so far as I know. You just have to be
- aware of the limitation and know that getting
- extremely close to your target carries a significant
- risk of collision due to a momentary warp. Get no
- closer than about .15 and you'll probably be okay.
-
-



GreyBeast_P39

XyZspineZyX
09-01-2003, 07:21 PM
Bump!

Collisions are not OK and need some attention.

Cheers

,,,^..^,,,

XyZspineZyX
09-01-2003, 07:45 PM
Yes Lag is a factor.

There is no way around it.


If the programer constructed the game to cause all collisions to damage all planes involved there would still be a problem associated with lag.

Because lag still exists.


The new problem would be:

"I moved out of the way and clearly the enemy plane trying to ram me was not even close to hitting me, yet my wing came off; Please fix this bug"



JG14_Josf

XyZspineZyX
09-02-2003, 08:05 AM
Yeah, the collision model is a bit wacky at times. The other day I was B&Zing an IL2, well, actually on the zoom climb, attacking from underneath. I looped around to see that I had cut the tail off the plane and it was going down, as I continued my loop I suddenly saw a pilot freefalling (Before his chute opened). He had his arms out looking like they do and I clipped his arm.

Suddenly I was spinning violently towards the earth minus one wing! To my surprise (As I panned around externally after becoming a ball of flame on the green floor) the pilot was gracefully floating to the ground in his parachute. He even ran once he hit the ground.

Apparantly, IL2 pilots are just as tough as their planes! LOL




Message Edited on 09/02/0306:48PM by Fehler

XyZspineZyX
09-02-2003, 08:45 AM
@BinaryFalcon
very good analysis!

I try short version for people unwilling to read the long:

- PC player1 calculates collision

- data starts travelling to PC player2

- in meantime PC player2 calculates slightly different flightpath, no collision

damage for a plane is calculated by PC of the player flying it, so player1 goes boom and player2 has no damage.



quiet_man

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