Backstab bugs?

[Sirnak]

Hello, everybody! Your favorite spy-monkey reporting for duty! I have a question for the widely TF2-experimented community of Critsandvich.

Is there a backstab bug in TF2?

Sometimes, as a spy, I hit my opponent in the back with my knife and there's no backstab occuring, making my foe ultimately turning back and... killing me. The thing is, I wonder if such a "bug" ever occurs to anyone else or if anyone happened to notice these unachieved backstabs. It happens to me a lot and I've seen it happening to other players who tried to backstab me or teammates so it's not a problem only me seem to have.

I have my theory about it, though. I believe that this "bug" occurs when the oppenent is turning around too fast. In such a case, even if the foe is still in a position in which he could be backstabbed, the result for the poor spy hitting a turning foe will be a regular and mostly useless knife stab sealing his fate.

Could anyone share his-her wisdom with me on the matter ? :3

Also, just for the sake of sharing this information with people who may not know it, I know another bug. But this one useful for spies. If you are close enough to an enemy that you can almost be inside of the character skin, a regular front knife hit will often result in a backstab. I often use this trick to survive when I have no solution left. It doesn't work everytime, but it's still quite useful.

[NuclearWatermelon]

One word: lag

The net-code in TF2 uses interpolation to help it all look smooth, what this means is that each client is predicting where everyone will be based on last known position and velocity, leading to instances where your version of the match does not match up with the servers.

When you shoot someone, or take a swing with melee, the client will start the animation and cue the sounds or what-have-you, but the server must determine what damage is done, and if you miss according to the server, oh well.

[Sirnak]

A... lag? Seriously ? I used to think it was the case, but I didn't want to believe it... Well, thanks for the answer Melonhead. :3

[Smeemo]

Yep. Same reason why sometimes it looks like you get killed by a heavy while behind a corner.

I don't know if this would work, but setting the value of cl_interp to 0.0152 (min value--default is .1) may help. .033 is ideal for hitscan weapons like your pistol, though.

[Toaster]

I don't think lag has as much to do with face/fail stabs as hit boxes do. If the backstabee is strafing while running forward the "back" isn't where it appears to be. The same thing applies for head shots. Make a server and turn on cheats/hitboxes and go thirdperson. You'll see the boxes change drastically when strafing and jumping or even taunting (while appearing to have no difference on the model it self).

(I could be wrong )

[NuclearWatermelon]

Knife doesn't use hitboxes, it uses collision hulls just like all melee weapons.

Collisions hulls are world-aligned, this is why you can have a longer melee range when you attack the hull at an angle.

[dieinafire]

I had a teammate today watch me stab a heavy in the back three times. Said heavy turned and shot me. If he saw me do it, three times, and I saw myself do it, three times, it doesn't sound like a client side lag issue.

[Sirnak]

I had a teammate today watch me stab a heavy in the back three times. Said heavy turned and shot me. If he saw me do it, three times, and I saw myself do it, three times, it doesn't sou

You make a good point, buddy. Now, would that mean the backstab bug is a global server lag? Nah, I'd tend to say, thanks to what you just pointed out, that it's all related to the "God Hates Me" syndrome.

According to the GHM, God will sometimes show you that life is cruel by making you fail terribly and randomly at anything you could possibly be doing. So, my own theory is that God sometimes watch TF2 players and decide that some backstabs don't work whenever he feels like it. :3

THAT, or... Maybe it's just a problem of information not getting send fast enough sometimes or anything like that... ? These are rarer occasions, but I already failed at backstabbing a Heavy standing by and not moving at all... I am in the good range and he doesn't move AT ALL, yet no backstab. This makes it unlikely that the backstab bug is a lag and the distance shouldn't be a factor either. Well, I'm just bringing ideas here... Though, I kinda like my GHM theory. ^^

[Vivi Hill]

I don't think lag has as much to do with face/fail stabs as hit boxes do. If the backstabee is strafing while running forward the "back" isn't where it appears to be. The same thing applies for head shots. Make a server and turn on cheats/hitboxes and go thirdperson. You'll see the boxes change drastically when strafing and jumping or even taunting (while appearing to have no difference on the model it self).

(I could be wrong )

I got an email a while back from Robin about that thirdperson glitch. He says not to trust those hitboxes, but rather to go on a server with a friend and try it. I tested it and it's true. The hitboxes when strafing and taunting are accurate in real life, just not in thirdperson.

Hi Gavin.
The bug is that thirdperson & sv_showhitboxes is not a valid way to see what the server hitboxes are doing.
Try testing it like this, and let me know if you still see issues:
“bot –class sniper” (or heavyweapons/scout/etc)
“bot_mimic 1”
“sv_showhitboxes 2” (the parameter is the entity index. You’re 1 on your own listen server, 2 will be the second player, 3 the third, etc)
Then run around a bit and see if the hitboxes look correct. They won’t be on top of the character (not relevant when determining actual hit detection, due to complex reasons), but they should animate properly.

Robin.

[Toaster]

Well that explains a lot, I was playing around with it for a few hours with kaynu. Good to know the hit boxes aren't that messed up

[VoltySquirrel]

I hate that shit. I've lost some of the most beautiful stab sprees due to the game not recognizing my perfect stabs.

[Sirnak]

I hate that shit. I've lost some of the most beautiful stab sprees due to the game not recognizing my perfect stabs.

You too, Squirrie? We should form a clan of animal spies that need to talk about this kind of things. Ya know, we don't need to remain in silence anymore. :3