fun with theoretical physicists

Sensei · Post by **Sensei** » Tue Jun 08, 2004 1:21 pm

Jigen wrote:Found a serious-ish bug... It's totally reproducable.

When double jumping forward, that is forward-forward, and aiming down at a certain angle, and firing the chaos grenade launcher, it ALWAYS explodes right in your face as if you were facing a wall. This is a pretty serious bug as this movement happens pretty often.

[edit : actually, you only need to be moving forward and down and facing down.]

Wouldn't that be running into your own grenade??

Jigen · Post by **Jigen** » Tue Jun 08, 2004 3:09 pm

Sensei wrote:Wouldn't that be running into your own grenade??

The laws of motion forbid this from happening. To run into your own grenade the grenade has to hit a surface first and bounce back and hit you. If you are launching the grenade midair and downward, it should not explode in your face. Only if you land directly on it when you LAND, not MIDAIR explosions... you see?

Brandon · Post by **Brandon** » Tue Jun 08, 2004 4:09 pm

Jigen wrote:
Sensei wrote:Wouldn't that be running into your own grenade??
The laws of motion forbid this from happening. To run into your own grenade the grenade has to hit a surface first and bounce back and hit you. If you are launching the grenade midair and downward, it should not explode in your face. Only if you land directly on it when you LAND, not MIDAIR explosions... you see?

Dude, that makes no scence, but it sounds to me like ur walking into your own grenade.

The Warlock · Post by **The Warlock** » Tue Jun 08, 2004 6:59 pm

Brandon wrote:
Jigen wrote:
Sensei wrote:Wouldn't that be running into your own grenade??
The laws of motion forbid this from happening. To run into your own grenade the grenade has to hit a surface first and bounce back and hit you. If you are launching the grenade midair and downward, it should not explode in your face. Only if you land directly on it when you LAND, not MIDAIR explosions... you see?
Dude, that makes no scence, but it sounds to me like ur walking into your own grenade.

Sigh... and we get into physics.

Motion is relative. The grenade should be fired (we'll discount air resistance for the time being, as it doesn't have any real effect here) at the same velocity, relative to the launcher (the gun) whether the launcher is at motion or at rest.

It's like this: If you are walking through the isle of a plane at a speed of, say, 1 MPH, and the plane is moving at upwards of 300MPH through the air, your legs don't need to move at 301MPH, do they? Of course not.

Likewise, let's say that the grenade launcher has a muzzle velocity of 5 ft/s. Now, if the guy holding the gun is leaping through the air at a speed of 10 ft/s, the grenade does not go -5 ft/s when fired by the leaping shooter. The shooter does not "run into his own grenade". Rather, the grenade is fired at a velocity of 5 ft/s away from the shooter relative to the shooter, or about 15 ft/s relative to a staionary observer.

Try throwing a ball slowly while you are running quickly. It's the same thing.

Zachariah · Post by **Zachariah** » Tue Jun 08, 2004 7:24 pm

The Warlock wrote:
Brandon wrote:
Jigen wrote: The laws of motion forbid this from happening. To run into your own grenade the grenade has to hit a surface first and bounce back and hit you. If you are launching the grenade midair and downward, it should not explode in your face. Only if you land directly on it when you LAND, not MIDAIR explosions... you see?
Dude, that makes no scence, but it sounds to me like ur walking into your own grenade.
Sigh... and we get into physics.

Motion is relative. The grenade should be fired (we'll discount air resistance for the time being, as it doesn't have any real effect here) at the same velocity, relative to the launcher (the gun) whether the launcher is at motion or at rest.

It's like this: If you are walking through the isle of a plane at a speed of, say, 1 MPH, and the plane is moving at upwards of 300MPH through the air, your legs don't need to move at 301MPH, do they? Of course not.

Likewise, let's say that the grenade launcher has a muzzle velocity of 5 ft/s. Now, if the guy holding the gun is leaping through the air at a speed of 10 ft/s, the grenade does not go -5 ft/s when fired by the leaping shooter. The shooter does not "run into his own grenade". Rather, the grenade is fired at a velocity of 5 ft/s away from the shooter relative to the shooter, or about 15 ft/s relative to a staionary observer.

Try throwing a ball slowly while you are running quickly. It's the same thing.

Yes but as the player falls through the air he has a greater mass than the Grenade , and thusly accelerates faster and catches up with his own grenade.

Kaboodles · Post by **Kaboodles** » Tue Jun 08, 2004 7:47 pm

No, Pepito.

Inertia counters any extra gravitational effect caused by having a larger mass. In fact, if you include air resistance, the player should be falling slower than the grenade, as the player is a bigger and less aerodynamic object.

Oh, and the error I kept having was easily solved by completely re-installing UT2004 and Chaos UT.

DUEL MELEE RULES!!!

I do have a few problems with some of the maps. Many times it would not allow me to respawn, so I have a bunch of bots running around killin' stuff without me.

Oh by the way, here's another error I found

UT2004 Build UT2004_Patch_[2004-05-10_17.18]

OS: Windows 2000 5.0 (Build: 2195)
CPU: AuthenticAMD PentiumPro-class processor @ 1537 MHz with 511MB RAM
Video: RADEON 9600 PRO (6343)

General protection fault!

History: APawn::processHitWall <- APawn::physFalling <- APawn::performPhysics <- AActor::Tick <- TickAllActors <- ULevel::Tick <- (NetMode=0) <- TickLevel <- UGameEngine::Tick <- Level Chaos Immortal <- UpdateWorld <- MainLoop <- FMallocWindows::Free <- FMallocWindows::Realloc <- 676F4C57 0 FArray <- FArray::Realloc <- 0*2 <- FMallocWindows::Free

I got this while playing last man standing duel with bots in the Due-ChaosImmortal map. It did this as the round ended.

The Warlock · Post by **The Warlock** » Tue Jun 08, 2004 10:00 pm

Pepito wrote:Yes but as the player falls through the air he has a greater mass than the Grenade , and thusly accelerates faster and catches up with his own grenade.

Wrong. Objects in the same gravitational field accelerate at the same rate. For Earth, that would be 9.81 meters per second per second. Mass doesn't figure into it. Air resistence can figure into this, but not enough to have you catch up to the grenade, especially for a little 5 foot jump.

TKATK · Post by **TKATK** » Tue Jun 08, 2004 10:06 pm

sorry to say but
1.Unreals maps arent situated on earth
2.its unreal?

The Warlock · Post by **The Warlock** » Tue Jun 08, 2004 10:10 pm

TKATK wrote:sorry to say but
1.Unreals maps arent situated on earth

Some are, and even if they aren't, it merely changes the constant, not the physics behind it. Besides, most maps use the same gravitational constant.

2.its unreal?

So? Does that mean that we should put up with this? If some vehicle just stayed in the air when you hit a jump, yould you put up with that? No, it would be a bug. Same here. You can't run into your own launched grenade. It's a bug. That's what this thread is for.

TKATK · Post by **TKATK** » Tue Jun 08, 2004 10:17 pm

The Warlock wrote:
TKATK wrote:sorry to say but
1.Unreals maps arent situated on earth
Some are, and even if they aren't, it merely changes the constant, not the physics behind it. Besides, most maps use the same gravitational constant.

2.its unreal?
So? Does that mean that we should put up with this? If some vehicle just stayed in the air when you hit a jump, yould you put up with that? No, it would be a bug. Same here. You can't run into your own launched grenade. It's a bug. That's what this thread is for.

2 things

1:CHAOS FIX!!!11!!!,errrm,leave it as it is,CHAOS DONT FIX !!!111!!!!
2:If realistic shooting like that was implemented it would certainly be a pain in the 3 stars,check excessives realistic rockets,not nice

The Warlock · Post by **The Warlock** » Tue Jun 08, 2004 11:45 pm

TKATK wrote:1:CHAOS FIX!!!11!!!,errrm,leave it as it is,CHAOS DONT FIX !!!111!!!!

Okay, what the ****?

2:If realistic shooting like that was implemented it would certainly be a pain in the 3 stars,check excessives realistic rockets,not nice

Umm... look, it's a bug. That's what the thread is for. This thread isn't for debating whether or not to fix them. A bug needs to be fixed, that's the way it works. Running into a grenade as you fire it is a bug. I don't care how they fix it, they just need to fix it.

Jeez, next you'd be telling Epic not to fix the weapon cycling bug because "it's too much work."

TKATK · Post by **TKATK** » Tue Jun 08, 2004 11:49 pm

1:A recreation of the classic EPIC FIX!!11!

2:i hope the incriesed projectile rate wont make the wep overpowered

The Warlock · Post by **The Warlock** » Wed Jun 09, 2004 1:12 am

TKATK wrote:i hope the incriesed projectile rate wont make the wep overpowered

Now you're twisting my words. The problem does not stem from the speed, but from the initial spawn point of the grenade combined with accelerating from zero. Make the projectile spawn firther out or raise the initial (but not the maximum) velocity and there is no real balance change, whicle at the time fixing the bug. That is, if the unreal engine does not allow the adding of vectors, which I think it does, as I've never had this problem with the Eightball.