Half-Life 2 Physics Detail?

[BabyHeadCrab]

I have a few questions reguarding the physics engine

1. Cloth phsyics? (forgot if they are included)
2. localized ragdoll effects (for example, you can get a dead arm if you get shot in the shoulder) and bone level blending of key-framed animation with physics.
3. Particles can also interact with other physical objects?
4. could wind / weather be faked such as a hurricane with objects actually being physically manipulated.
5. Physically simulated projectiles.. bullet comes down after you shoot it? I know it is discussed that you can pick between actually projectiles or hitscan and you can make them actual objects.. so if you did do this would they have colision detections and such.. so like could I make a live chicken launcher.. that would make the chicken shoot sqeal really load and have feathers realisticly float down as the chicken ragdolled dead?
6. physically simulated hail or "x" for instance could I have it raining toads? or toads that actually are still alive and run around and croak! and have the objects break dissapear or physically affect other non static objects (break surfaces) or otherwise.

still thinking of things. Kudos to MoeJoe for inspiration with his tech demos from meqon phy.

 

[marksmanHL2 :)]

I have a few questions reguarding the physics engine

1. Cloth phsyics (forgot if they are included)

Dunno...


2. localized ragdoll effects (for example, you can get a dead arm if you get shot in the shoulder) and bone level blending of key-framed animation with physics.

EDIT: I am saying "NO" now because Chris_D knows his stuff

3. Particles can also interact with other physical objects?

Yes. Just look at the tunnels vids/bink.


4. could wind / weather be faked such as a hurricane with objects actually being physically manipulated.

Yes. Valve said they made a mini torrnado once for a laugh


5. Physically simulated projectiles.. bullet comes down after you shoot it? I know it is discussed that you can pick between actually projectiles or hitscan and you can make them actual objects.. so if you did do this would they have colision detections and such.. so like could I make a live chicken launcher.. that would make the chicken shoot sqeal really load and have feathers realisticly float down as the chicken ragdolled dead?

Yes... you could indeed have such a chicken launcher...


6. physically simulated hail or "x" for instance could I have it raining toads? or toads that actually are still alive and run around and croak! and have the objects break dissapear or physically affect other non static objects (break surfaces) or otherwise.

I would gess this could be modded in without a problem considering they can now make it rain objects in a DC minimod (Mod for the BF1942 engine)




K?

 

[Chris D]

1. no
2. no
3. yes
4. yes
5. I assume so. Sounds quite basic
6. again, I assume so.

 

[guchi]

1. im not sure, probobly not
2. not sure
3. yes
4. most probobly
5. this isnt in hl2 as a design choice, but yeah im sure you could (read it somewhere)
6. that would be very cpu craving, but you could just have lots of spawn points in the sky...

 

[BabyHeadCrab]

thanks marksman.. good to know my chicken launcher is still in order.

kind-of sad that about the first 2.. cloth phsyics are in Unreal Warfare (which is clearly getting dated already) also keyframe blending seems like it is quite basic.. I think to a basic level it is included.

 

[marksmanHL2 :)]

nps. Glad to help. :cheese:

 

[BabyHeadCrab]

so much for my theatre curtain in the sourceworld map I could have made ):

a static curtain is just.. lame (either a hard wall or nothing at all) :| im suprised about the lack of cloth physics.. isint that in havok 1?

 

[W4E]

Chicken launcher??
Toad rain??
an FAQ somewhere said the answers to alot of them. ill try finding it.
who do you mean by YOU in "you can get a dead arm if you get shot in the shoulder"? do you mean the player or the other people in the game?

PS "cloth physics" is not a question.

 

[Chris D]

BabyHC, it will be along time yet before we have fully simulated cloth physics.

A talented animator/modeller would be able to animate a realistic curtain.

 

[BabyHeadCrab]

BabyHC, it will be along time yet before we have fully simulated cloth physics.

A talented animator/modeller would be able to animate a realistic curtain.

Dude the meqon type as seen in the 1.8 mb demo would be fully acceptable kplzthx (never implied I meant fully simulated)

see demos: http://meqon.com/downloadarea/downloadarea.php

 

[guchi]

there where cloth physics in splinter cell...

 

[marksmanHL2 :)]

BabyHC, it will be along time yet before we have fully simulated cloth physics.

A talented animator/modeller would be able to animate a realistic curtain.

I'm thinking it wont be all that long.

Afterall... HL2 has rope physics. Cloth physics are surely just an extension of that. ie the same technology on a plane rather than a line if you will.

 

[BabyHeadCrab]

I was thinking.. like lots of joints.. like several ropes together only flatter... im sure that's how meqon/havok2 are doing it...

 

[Chris D]

:|

I got mixed up. It's cloth physics that are the easy ones. The water physics is the difficult one to do.

 

[W4E]

i quite sure HL2 will have cloth sim.
guchi said splinter cell has it.
hitman 2 has it.
i think maxpayne 2 has it.
and HL2 looks to have more technologicaly better stuff than those games.

 

[Crusader]

1. Yes, it's even been in 120k Havoc demos.
2. I had thought no. But someone "confirmed" they did have a little while back, notice the quotation marks. I am not sure on this.
3. Yes.
4. yes
5. Yup.
6. yes but very cpu intensive.

 

[SnowBall]

:|

I got mixed up. It's cloth physics that are the easy ones. The water physics is the difficult one to do.

Water can be simulated physically to an extent right now. Such as ripples, waves, etc.... Just cant do pouring and such.

 

[Chris D]

Water can be simulated physically to an extent right now. Such as ripples, waves, etc.... Just cant do pouring and such.

Yeah, I meant the latter.

 

[Bluetooix]

1. Cloth phsyics (forgot if they are included)

Soft body kinetics aren't included in source from what I know.

2. localized ragdoll effects (for example, you can get a dead arm if you get shot in the shoulder) and bone level blending of key-framed animation with physics.

No, again from what I've heard, bodies (as a whole) go inert only after they are dimsed. I think the other thing you asked was talked about in a long thread. Someone e-mailed Gabe and it was rejoined with a "someone could mod it".

3. Particles can also interact with other physical objects?

Fire interacts from what I've seen, so yeah. Though it is the material system that is doing it

4. could wind / weather be faked such as a hurricane with objects actually being physically manipulated.

An employee at valve did this I heard.

5. Physically simulated projectiles.. bullet comes down after you shoot it? I know it is discussed that you can pick between actually projectiles or hitscan and you can make them actual objects.. so if you did do this would they have colision detections and such.. so like could I make a live chicken launcher.. that would make the chicken shoot sqeal really load and have feathers realisticly float down as the chicken ragdolled dead?

In the game I think it'll just be a point to point system. So it travles in a line until it is impeded by something.

6. physically simulated hail or "x" for instance could I have it raining toads? or toads that actually are still alive and run around and croak! and have the objects break dissapear or physically affect other non static objects (break surfaces) or otherwise.

Not to sure about this.

 

[mutt]

Dude the meqon type as seen in the 1.8 mb demo would be fully acceptable kplzthx (never implied I meant fully simulated)

see demos: http://meqon.com/downloadarea/downloadarea.php

wow that demo is great, hl2 doesnt have liquid physics like that does it? or cloth

 

[urseus]

If it doesnt have coth, im sure it will be implimented in mods very soon afterwoods.


Water interaction seems to be the one nut everyone cant crack. But it is kinda cool to be knee deep in gaming at this point when gaming engines are advancing into new relms like this. Physics in games feels like a new generation, like the introduction of real 3d over sprite based graphics.

 

[wayne white]

why dont someone mail those questions to valve?(pretty good questions all).

 

[Bluetooix]

it doesen't have fluid kinetics but it will react to objects that fall into it. It does react to objects that fall into it realistically but it just won't pour i.e. an e-mail in the pinned thread above to valve had someone ask if holes were added into a box holding water if the water would pour out. It won't but you could animate it like valve did in the original.

 

[urseus]

^^^how come?


Like in really old games i can remember shooting a barel half way and oil coming out of it to the hole, then if i shot further down the oil would come out untill the hole again. Surly it wouldnt be that hard to replicate the water level lowering inside the barrel, and have a sprite of water come out.

 

[lans]

:|

I got mixed up. It's cloth physics that are the easy ones. The water physics is the difficult one to do.

I'm hundred percent sure that the splinter cell 3 engine is capable of cloth physics as sam actually cut through it and it reacted realistically when he passed through. (e3 2004 video)

 

[BabyHeadCrab]

Water can be simulated physically to an extent right now. Such as ripples, waves, etc.... Just cant do pouring and such.

actually no. The water isin't phisically there it's just a gravitationally different zone fit with scripted animations... water simulation pours and seeps.. it physically represents water. which is right next to impossible with the amount of cpu cycle it would take up with equations. if it were to be simulated like a solid is represented (to it's fullest) the equations would be limitless.. liquid is just so seepy

 

[Bluetooix]

^^^how come?


Like in really old games i can remember shooting a barel half way and oil coming out of it to the hole, then if i shot further down the oil would come out untill the hole again. Surly it wouldnt be that hard to replicate the water level lowering inside the barrel, and have a sprite of water come out.

You can simulate that without having fluid dynamics.

actually no. The water isin't phisically there it's just a gravitationally different zone fit with scripted animations... water simulation pours and seeps.. it physically represents water. which is right next to impossible with the amount of cpu cycle it would take up with equations. if it were to be simulated like a solid is represented (to it's fullest) the equations would be limitless.. liquid is just so seepy

Forget what I said. I understand what you mean. Actually being physically simulated and using scripts to alter whatever enters the area. I'm sorry about that if you did read it.

 

[Bluetooix]

sorry to double post but I made a typo above. Actually being physically simulated instead of using scripts to alter whatever enters the area.

 

[urseus]

To fully simulate water, a pool would have to be mad up of trillions of tiny water models, each with their own physics system, each reacting independantly on its own with anything it comes into contact with. Youd need some kind of Skynet computer to run it. Once you have computing power like that though, youd only have a short time to play the game before the war begins.....double edged sword.

 

[ZeeM]

guys remember the source engine demonstration from e3 2003 and the traptown video? there was a mattress there which was acting like a real... mattress :cheese:
so there are cloth physics :bounce:

 

[Vegeta897]

1. no
2. no
3. yes
4. yes
5. I assume so. Sounds quite basic
6. again, I assume so.

I think the mattresses use cloth physics... Just with more restricted bendability.

 

[Cyanide]

Even if Source doesn't have true cloth simulation, it wouldn't be to hard to fake it. Remember the matress from the first e3 demo? It was just a ragdoll, but you could just make that matress thinner, redo the contraints of it's joints, maybe added some more joints, and gave it a new texture, and you would essentially have a peice of cloth that would work well as a cape or something. Real accurate cloth simulation is very CPU intensive. So if it is in Source, you'd only want to use it with a few characters on screen or if the rest of your world had a low polygon count.

BTW, cloth and softbody dynamics are not the same thing.

I don't know about localized ragdoll, but according to Merc (the guy who playtested the game) the enemies do react to being shot, which would suggest bone level animation blending with physics. I think I remember reading that the legs of the strider are partially physicly simulated, and partially animated. Don't take that as a fact though.

I would imagine particles could interact with other objects. Considering that the particle system is capable of producing sprites or models. It would definately take you out of the emersion if you saw a vehicle explode and the pieces of metal that fly off don't behave like physicl objects when everything else around them does.

Yes, you definately can make wind, and it interacts with physical objects. As shown by the gunship in the e3 video.

Even very old games were capable of simulating balistic projectiles. If Source can't do it I would seriously be shocked that they would omit something that important to FPS games. I don't know about the feathers though. That would require accurate drag and aerodynamic calculations to properly simulate. I don't know if the physics is that detailed. If you could do that, you could make a plane with a real physicly simulated engine that drives a physicly simulated propeller. You could then make the propeller out of wood, and if it was shot, it would break apart and the plane would realisticly loose altitude and crash. That would be cool if you could do that. But I don't know that you can. Even if you could, it would proabably be pretty CPU intensive.

Gabe has said before that the physics system "runs out of gas" when you have lots and lots of objects. I imagine you could make it hail, but to have the hail be physicly simulated would would probably not work. The best way to create an effect like hail would probably be to have a particle emiter that follows the player and surrounds them out to a reasonable distance. That way you're not simulating things that the player can't see. Then you could just cover the ground on the map with lots of unphysicly simulated hail stones, to make it appear as though it's hailing across the entire map.

BTW, here's a link to the Source engine features page.
http://www.valvesoftware.com/sourcelicense/enginefeatures.htm

 

[Bluetooix]

No those are made with hinge joints (which still are rigid body form). The mattress is made up of them.

BTW, cloth and softbody dynamics are not the same thing.

cloth dynamics is a softbody form.

Splinter Cell which used a customized unreal engine had cloth simulation.

 

[poseyjmac]

i dont think it will, because if you notice, all of the models dont have 'flowing' clothes, which is a good excuse not to include cloth sim.

 

[tommie]

AHHHH TORNADO!!!! I'd love to see that!

But a HURRICANE in HL-2, I think you'd need a Radeon from the year 3000

 

[AJ Rimmer]

i dont think it will, because if you notice, all of the models dont have 'flowing' clothes, which is a good excuse not to include cloth sim.

well, why bother to have clothes in the game at all? Of course, then maybe something else would be flowing in the wind

 

[Alec_85]

Cloth simulation is quite hard I think. Heck, even the guys behind the 2 latest Star Wars movies had problems with it :E That's quite clear if you check the behind-the-scenes on the DVDs.

 

[poseyjmac]

well, why bother to have clothes in the game at all? Of course, then maybe something else would be flowing in the wind

i completely agree...concerning alyx anyway :cheers:

 

[guchi]

i belive i heard somewhere in the depths of the valve info thread that you could turn on flowing clothes for characters, but that it would seriously kill your cpu... im not sure if this is correct though, i may be wrong...

 

[Bluetooix]

AHHHH TORNADO!!!! I'd love to see that!

But a HURRICANE in HL-2, I think you'd need a Radeon from the year 3000

Hardly. I think a tornado would be more fun to play around with. It sucking boxes around at high velocity and throwing them out. Thinking about a pipe or metal box hitting the combine just makes me quezzy. Sucking up dead bodies and tossing them wildly on the ground or building would just be awesome.