Physics discussion?

[Raziaar]

Hey, I tried doing a search, but I cant find any topics that are just really 'physics' discussion. Well, except for ones that have beta information. I dont like reading that stuff. And they all get locked anyways.




I can't wait to screw around with the physics in half-life 2. I haven't experienced realistic physics 'all around' in any other game. Max Payne 2 had PIDDLY physics if you ask me. If I shot a vase, it didn't go flying! ARGH. It was SOOOO dumb.

I'm gonna try everything when I get the game. I think after playing it half-way through i'll try to make a map and screw around and make all knids of weird physics things to have fun. Domino effects, giant bowling ball lanes, you name it!


One thing i'm curious about physics... if the manipulator has a max weight limit, and a car is a certain weight 'near' that weight limit, but not exactly. A little heavier. Can you actually pick up the car and 'drag' it around? like pick up half and the other half is dragging on the gronud? That would be SWEET!

But somehow I think its impossible for the engine to simulate this.

 

[ShinRa]

Its not impossible if you set joints on the car model, and make one side heavier than the other, then the physics would work accordingly. But if its too heavy for the manipulator to pick up, it wouldnt even lift off the ground..

 

[dream431ca]

can you some how set the manipulator gun to pick up things heavy like a car?? I know in most games you can go into the system.ini file or whatever it's called for HL2 and change how much force it can pick things up.

 

[dream431ca]

You also can probably change the force it shoots things as well.

 

[Brian Damage]

Well, I think this has been dicussed recently, in the "Physics Tricks" thread. But I want to make a big ramp, and do buggy jumps.

(You could have just edited your original post, dreamwhatever.)

[EDIT]: Here it is:

http://www.halflife2.net/forums/showthread.php?t=20993&highlight=physics+tricks

 

[Dead-Inside]

I prefer a new thread.

I'm not sure exactly on what I'd do seeing as how I won't create new content outside that of what is avavible within the map editor coming with the game.

I'd probably do something as I saw in a Halo-video once, jump with a buggy like the crazy man I am.

It'd also build a rollercoaster out of either wood, metal, or a little bit of both. You line up the car, and keep a certain speed, or you die or fall out of the coaster, how awesome is that?

Last thing I can think of is a submarine-map... I mean... Awesome or what? Travelling around sinking mercenary and royal fleet ships as a german submarine commander in WW2, anyone?

 

[Play4Fun]

after Abom closed my thread ;( I had to post my questions here.. :hmph:
OK, its a stupid question but I was wondering if i'll throw a mattress on a Combine do u think he'll die? :frog:
and that leads me to another question, do u think that if I press the "throw" button alittle longer (while I'm lifting an object with the Manipulator) it will add more speed and power? :O

 

[figge]

I'm going to make a Pinball map! muhahahaha!


Manipulator + Ball + Combine + Ramp

 

[Lobster]

I hate discussing the beta but somone on one of those dodgy sites made a map of a mountain cable car with physicly simulated cable cars swinging on cables, that acctully ran on a pully system and could be blown up and snapped lol.

I just cant wait to see what people create when the games out, I can picture a whole fairground of stuff to muck about on lol.

 

[dream431ca]

Someone should try to make a carmageddon map. That would be interesting.

 

[DreamWraith]

or not.

(damned 10 character n00b limit)

 

[Daiceman9]

in the beta there was a command to change the max weight lifting capacity of the maniuplator.

 

[PatPwnt]

in the beta there was a command to change the max weight lifting capacity of the maniuplator.

What was the command?

 

[Raziaar]

It'd be cool as you progress in the game Eli or another scientist can make modifications to the manipulator gun so that its carrying capacity can be increased.

 

[chu]

One thing that annoys me with physics is when you shoot a cardboard or wood box and the box doesn't break apart but just flys across the screen. That bothers me.

 

[Raziaar]

Yeah. Thats dumb. Thankfully we wont HAVE that in this game! WOOOOT!

 

[63]

can you some how set the manipulator gun to pick up things heavy like a car?? I know in most games you can go into the system.ini file or whatever it's called for HL2 and change how much force it can pick things up.

Welcome to the wonderful and wide world of Modding my friend!

 

[Raziaar]

Know what mod we need? Mousetrap!

What a fun experiment that'd be setting up! AHaha. Ahh, if only I were a kid again.

Actually though, I think setting up a gigantic complicated domino system will still be one of hte most fun for me. IMigine the dominoes life sized and adding other elements to it as well to make it even more interesting :-P

 

[Raziaar]

I know the physics system is powerful. But would it be possible you think to make something like a bowl with a ball in it, having the bowl move and the ball rolling around inside realistically and fluidly continuously? Or how about a giant roulette wheel with a ball inside? I would think that much constant, perfectly fluid motion would bring the system to its knees.

Do you think something like that would be possible? I'm mainly thinking round objects that roll around all over the place( I wanna build a crazy contraption)

 

[|Link|]

i dont think that fluid reacts to physics ( for example u shoot a container filled with water and it squirts, drips)

 

[Dead-Inside]

Link, he wasn't talking about water/floating content, he meant if it'd run smooth. However you're correct that Source can not simulate water in that manner, NO engine can on today's market.

Raziaar,
Most probably, yes. It'd be strange otherwise seeing as ragdolls keep momentum after they die.

 

[Reiska]

One thing i'm curious about physics... if the manipulator has a max weight limit, and a car is a certain weight 'near' that weight limit, but not exactly. A little heavier. Can you actually pick up the car and 'drag' it around? like pick up half and the other half is dragging on the gronud? That would be SWEET!

But somehow I think its impossible for the engine to simulate this.

I dont think thats impossible at all. Have you checked out the new E3 vids? In the one where Gordon spanks "hanged" zombie with crowbar and then picks up a wooden platform with manipulator, it is clearly something heavy (unlike some ammo Gordon picks up with manipulator in other vids) and drags along the ground from far first.

 

[ferd]

all this talk just makes me a bit less patient

 

[figge]

/me thinks Indiana Jones with that large boulder...


Things i will try to make with Source:

Flipper
That Marble Game with holes and stuff... (laburinth)
Baloons!

I wonder if you can sett something to minus... like a baloon and make it float...

 

[PatPwnt]

/me thinks Indiana Jones with that large boulder...


Things i will try to make with Source:

Flipper
That Marble Game with holes and stuff... (laburinth)
Baloons!

I wonder if you can sett something to minus... like a baloon and make it float...

Yea, you can set negative gravity.

 

[Runteh]

In the E3 vid he makes the buggy move by shooting it with the manipulator's other firing mode. I dont think you can drag anything that is too heavy, the manipulator just doesnt work if its overweight I guess. Plus map makers may run into loads of issues if you can drag things overweight with the manipulator, so that may be the way it perhaps is.

I am sure you could mod it though, seems very basic in terms of physics coding.

 

[Raziaar]

Map makers wont run into issues. Cause they can just set things to not be able to be utilized by the manipulator most likely, even if they can be reactive to physics.

 

[Raziaar]

One more thing. I'm wondering how capable this physics engine will be for simulating flight. It struck me that when Gordon picked up the sign of ravenholm that when he shot it, it flew much shorter and differently than say a metal barrel. I know objects have mass, but I'm kinda guessing they also produce drag depending on how they are designed too. It sure seemed that when he shot the sign it didn't fly up very far because it had so much drag characteristics.

I was also thinking if you modelled a paper airplane or something with very low mass, but very decent flight characteristics, would it actually 'glide' in the game? Or will it just fall to earth like a stone? Will all objects just fall to earth like a stone? TO make a game like bf1942 with the source(the developers of half-life 2 said its possible if you scale the engine), will they have to cheat flight physics like bf1942 did? It didn't have true flight characteristic physics.

 

[PatPwnt]

in the leak it seems flat and less air resistant objects fall slower.

 

[|Link|]

in the e3 video, the part with the zombies and the legs tied to the trees he manipulates the sign and throus it and it looks so real

 

[Raziaar]

I'm gonna send gabe an e-mail. That is, if someone else already hasn't done this.

 

[Scapegoat]

I dont think thats impossible at all. Have you checked out the new E3 vids? In the one where Gordon spanks "hanged" zombie with crowbar and then picks up a wooden platform with manipulator, it is clearly something heavy (unlike some ammo Gordon picks up with manipulator in other vids) and drags along the ground from far first.

It's not because it's heavy, it's because it's further away (or I assume so). Naturally the pulling force of the manipulator would be strongest in front of the manipulator, and it would get weaker the farther away. This is shown in the E3 videos when he picks up the roller-mine from afar, a dead combine's gun from afar, and, like you said, the crate.

 

[Reiska]

It's not because it's heavy, it's because it's further away (or I assume so). Naturally the pulling force of the manipulator would be strongest in front of the manipulator, and it would get weaker the farther away. This is shown in the E3 videos when he picks up the roller-mine from afar, a dead combine's gun from afar, and, like you said, the crate.

You could be right. Lets see if Gabe or someone from valve answers.

 

[Raziaar]

I put all of ricks replies in quote form. to distinguish them.

Hi Raziaar,
See my answers below.

Thanks,
Rick
Valve

-----Original Message-----
From: Raziaar [mailto:********(took my e-mail address out)]
Sent: Monday, May 24, 2004 4:03 PM
To: Rick Ellis
Subject: Source Physics Engine: Flight?


Hello Rick!

I've e-mailed to ask about the source engine and its ability to simulate
flight.

It struck me that when Gordon picked up the sign of ravenholm in one of
the 2004 E3 demos, and shot it, it flew a much shorter vertical distance
than say, a barrel might. I know objects in the game have mass, but i'm
also guessing they also produce drag if their shape would realistically
do so. It sure seemed that when he shot the sign up it didn't fly as far, and
so much differently because of its drag characteristics.

*** Well there is drag in the game and there objects also have mass.
The lower mass of the sign would mean it would have less momentum when
it had the same force applied to it that the barrel has (think what
happens if you get hit at 5 mph by a bicycle vs. a car

I was also thinking, that if you modelled a paper airplane or something
with very low mass and decent flight characteristics, would it actually
'glide' in the game? Or would it just fall to earth like a stone, and if
so, do all objects just fall to earth like a stone? You guys said in the
past its possible to make a game like bf1942 using the game engine, if
things are scaled appropiately, but if you did, can you have a more
realistic flight model than that game, or would you have to cheat the
flight dynamics like they did to achieve it?

This might be possible, however a paper plane has lift created via the
wings that it has, which means it would fly instead of fall (all objects
without lift fall given gravity). You could simulate this in a mod if
you wanted by setting the gravity to something other than 1.0 for that
object. We do some of this with things like grenades to make them have
lofty trajectories instead of flat ones (they look more realistic that
way).

If you could answer these questions, it would be greatly appreciated!

Sincerely, Raziaar

 

[BiG O]

In light of this physics discussion, I was curious whether it'd be possible to simulate centripetal force? For instance a pole that had a rope attached to the top of it, and an object attached to the opposite end of that rope. The pole would spin around in place and the object would in turn twirl around. This is simple physics so far, so would you then be able to shoot out the rope and send the object flying in a straight line?

My appologies if this was already covered in an earlier thread.

 

[Darkknighttt]

probably lots of things are possible with the physics. is there a water flowing code for unreal 3 engine?!

 

[-=Nemesis=-]

If I shot a vase, it didn't go flying! ARGH. It was SOOOO dumb.

I don't know if you live in the real world but unless the vase was bullet proof it would never fly because of a bullet impact.

One thing that annoys me with physics is when you shoot a cardboard or wood box and the box doesn't break apart but just flys across the screen. That bothers me.

You do know cardboard is more like paper hey, please try shooting it irl. I don't see it breaking apart and the same goes for the wooden box. Unless you pump it full with lead or a close shot from the shotgun, else the bullets would just penetrate the wood/cardboard.

I think the physics are great in HL2 as far as I've seen them on the vids.

 

[Raziaar]

I don't know if you live in the real world but unless the vase was bullet proof it would never fly because of a bullet impact.



You do know cardboard is more like paper hey, please try shooting it irl. I don't see it breaking apart and the same goes for the wooden box. Unless you pump it full with lead or a close shot from the shotgun, else the bullets would just penetrate the wood/cardboard.

I think the physics are great in HL2 as far as I've seen them on the vids.

I used a bad example there. Forgive me. Basically what I meant was, things weren't able to be interacted with. If they put a solid metal box on the table, and I shot it, it wouldn't go flying. At least from what I remeber(only played it once through, didn't like the game or the story).

About the boxes. That whole thing that I was talking about which was dumb, was with max payne 2. Again, another bad example. FORGIVE me. What i'm basically saying, is that I *LOVE* how physics are implemented in half-life 2 compared to max payne. Max payne wouldn't go down in my books as a physics igame. Ragdolling maybe.

Anyways, I never said bad htings about half-life 2 physics. I LOVE them. All that was about max payne 2

 

[UltimaGecko]

In light of this physics discussion, I was curious whether it'd be possible to simulate centripetal force? For instance a pole that had a rope attached to the top of it, and an object attached to the opposite end of that rope. The pole would spin around in place and the object would in turn twirl around. This is simple physics so far, so would you then be able to shoot out the rope and send the object flying in a straight line?

My appologies if this was already covered in an earlier thread.

I don't mean to be the physics nazi over here... Heil Physik! ...but:

Centripetal Force = center seeking
Centrifugal Force = center fleeing

In actual Newtonian physics, Centripetal forces and motion do not exist. Nothing physically is drawn to the center of a path of motion. It is just prevented from making use of its inertia and continuing in one direction by the counter-to-centrifugal force (which many people mistake for a centripetal force). The fact is this is usually caused by friction.

In your example it would be the tension in a rope; if you swing a bucket around, it's the (...speed you swing the bucket and its pressure on the side of the bucket) bucket's structural stability; if you turn a car around a sharp curve, it's the tires friction with the asphalt.

The only true time you could apply the characteristic of centripetal force would be through gravity and electromagnetics (and probably nuclear forces too, but I'm not big on the internals of atoms), and that'd be force of attraction instead of centripetal force (although I suppose you could label it as such if you were orbiting it around a point).

Thought it might be something you'd want to tell your friends . Hopefully you can tie things together with the high quality, nice looking ropes - that'd be an awesome experiment to test the physics engine.


...On that note: I'm going to try to make a perpetual motion machine with a bunch of spheres...maybe on ropes. I'll knock them together (hanging, or in a bowl-ish shaped object) and watch them go...and I'd just keep adding more and more spheres - maybe reduce friction in the game if it exists so they really can go forever.

...Or just re-make the pachinko machine from the E3 2003 demo. You could make a mod where you play pachinko before every level and you get something for which peg slot the barrel hits at the end...heh.

...maybe I just need to lay off the physics and play the game first...heh. It's going to be awesome for the physics alone (especially if they're very easy to fine tune with lots of options).

[and unless your vase is made of highly elastic rubber coated kevlar I sure hope it wouldn't bounce around when it's shot; on another note generally when you shoot metal crates on tables the momentum of the bullet isn't going to move the crate. Simple mathematics .002kg (slightly small bullet, but that's okay) X 500m/s = 1kg x 1m/s (plus friction to move it accross the table)- and that's assuming your crate only weighs 2.2 pounds]

 

[jameslheard]

this is some info about physics in the beta. their is no story line in it and i have not mentioned any maps that come with the beta. only custom made maps which test the physics.

Spoiler

I have seen maps made for the beta and most of what is talked about is possible. For example it is possible to have a ride like http://www.ride-extravaganza.com/rides/enterprise/enterprise_03.jpg. which reacts in the same was as real things would when spinning. Also their has been several maps made which are large hollow balls that are spinning with watermelons and rag dolls in them and they move and bounce around in it fluidly with no lag. on a 3200+ xp and 9800 pro not sure about lower spec cards but from what i have heard they also work fine. also before people moan about how this is unfair on valve and how they would not be happy about people making these maps i will say this. I can safely say that valve know about these sites and if they so wanted could ask that things be removed from them but they haven’t so...