Physics and Multiplayer 2ghether???

[J Hater]

well correct me if i'm wrong but i heard multiplayer is going to have no physics and as far as i've seen no game that had physics in singleplayer also had them in multiplayer.
So i ask u ppl is it confirmed that multiplayer it's gonna support physics?

oh and hello everybody i'm new here my first post on this forum!

 

[EVIL]

hl2 will have em in MP, they answered some questions about how psychics where handeled in MP 6 months back or so. smaller stuff like small rocks are handeled by the client but large things like boxes and stuff are handeled by the server or the other way around, it should be in the valve question thread.

EDIT: and welcome to the forums, I hope you will have a pleasant stay

 

[WhiteBoy]

No one knows this other then Valve themselves. I sent an email message to them a couple weeks addressing this question, but they obviously ignored it. I believe they won't say anything about the multiplayer side of Half-Life2 for a while if at all before the release.


EDIT: Well after reading the post above mine it would appear we do know a small amount about the multiplayer portion.

 

[gesto21]

Halo, UT2K3, UT2K4, Farcry all have MP physics. Perhaps not the level of physics that are present in single-player, but they're there. To have fully-functional physics in MP, everything has to be synchronized perfectly, or you'd end up with a barrel at the bottom of the stairs on one machine, and leaning against the wall on another. This takes up valuable bandwidth. Dead bodies and other non-interactive flying debris can be done client side- and if you watch 2 machines playing the afformentioned games side-by-side, you'll see that dead bodies end up in different locations on each. One of the reasons they didn't make Halo co-op on the PC was this restriction.

 

[Rupertvdb]

yeah they have mentioned in interviews that they shall have the map maker denote that which is physically simulated server side and that which is simulated client side, this means that you can have barricades being made and bridges being shot out but certain things shall be different for everyone. Hopefully this wont be too hard to organise, i don't want to shoot razor blades at people with my manipulator and find that it isn't happening to them.

 

[Pi Mu Rho]

It'a already been stated that it's up to the modmakers what stuff is handled client-side, and what is handled server-side.

It's entirely possible to have physics in multiplayer - Valve have mentioned it with regard to vehicles. You just won't be able to have 32 players and full physics on everything.

 

[Pi Mu Rho]

Damn you, Rupertvdb. Damn you to heck.

 

[Polykarbon]

I really hope they allow a server command for ragdoll animations to be server side...

 

[Pi Mu Rho]

The more stuff that is serverside, the more packets are going to need to be sent/received. It could end up as lag city.

Why would you want serverside ragdolls anyway?

 

[Murray_H]

The more stuff that is serverside, the more packets are going to need to be sent/received. It could end up as lag city.

Why would you want serverside ragdolls anyway?

example:

<b1ker_boI> LOlzzzz look at teh way teh raggy dollz are, dey be bumming!
<NEo_Mttrix_2k1> WTF nub, dey be just on teh ground

we can share the humour of kills

 

[Pi Mu Rho]

That's what screenshots are for

 

[Wsh]

we can share the humour of kills

I agree 100%. It much more fun when everyone sees the same thing.

 

[Caster]

Not when it includes massive amounts of lag!

 

[Polykarbon]

Ragdolls, barrels, crates, wood, etc--really will not cause that much lag.

Considering what I have read from people who played the leak on a network, I would say that the netcode is pretty solid [Won't go into it]

There are SEVERAL things you can do to control the lag with the physic enabled objects.

One of the first things I look foward to doing as a programmer, is straining the netcode and pushing things as far as I can.[Multiplayer]

Then you can come to a great conclusion of what you can/can't do without doing heavy changes to the netcode itself.[A seperate server database is one thing]

 

[Beserker]

hl2 will have em in MP, they answered some questions about how psychics where handeled in MP 6 months back or so. smaller stuff like small rocks are handeled by the client but large things like boxes and stuff are handeled by the server or the other way around, it should be in the valve question thread.

EDIT: and welcome to the forums, I hope you will have a pleasant stay

This means that MP will have full physics with the client and the server working together...50/50?

 

[J Hater]

damn i posted the thread like a few hours ago and now i have so many replies it's very good to see that this forum is very very alive! and not like other forums where u get a reply like after 2 days . thanks for the answers

 

[Axyon]

This means that MP will have full physics with the client and the server working together...50/50?

Pretty much, yeah. The smaller, insignificant items are client side so as to not create any more unnecessary activity for the server. If every small object, like a rock or can was synchronized, the server would be under much more strain. Again, that's why ragdolls are client side by default, they don't affect the gameplay in any way apart from being visually attractive.

 

[Dougy]

Ragdolls, barrels, crates, wood, etc--really will not cause that much lag.

Considering what I have read from people who played the leak on a network, I would say that the netcode is pretty solid [Won't go into it]

Thats LAN.

Lan is a ton faster than even the best Cable connection availible for the net.

So no everything you mentioned will lag a lot.

 

[Subz]

imagine having a huge city map just with destroyed/wrecked cars...a few working buggies and manipulators. Car-toss ownage. (could be easily modded i guess)

 

[Polykarbon]

Thats LAN.

Lan is a ton faster than even the best Cable connection availible for the net.

So no everything you mentioned will lag a lot.

...

I was not talking about a local area network. There was a major stress test done with the HL2 leak with the netcode in the game. 10-15 people in a server with large numbers of synced physics being used at one time...VERY stable. There are also pictures out there of 50+ buggies in a map with several people, and a grenade is thrown and the buggies react accordingly without a strain on the main server or those connected. It isn't like the people were testing the game on a local network :-/...you could have almost infinite physical objects because the latency would be 0-10.[or just 0 on a 10/100 hub]

I have written a bunch of netcode physics alg properties that involve Collision Detection and Contact Generation Algorithm primitives. Generally when you code physics over a network, you have to deal with 3 major mesh types. Spheres, boxes, and cylinders. Convex mesh, mesh, triangle lists and others--which create your more complex physics...such as vehicles, the flexible bed, etc. Primitive objects represent the fastest collision types and being on smooth surfaces allows for low latency physics over a network. The main problem occurs when the surfaces interact with each other, but this still isn't a problem because you use client-side prediction for this.

I really don't understand where people get the general idea that physics automatically = lag. It doesn't, as long as you follow simple logic programming principles and are not a sloppy coder overall...which yahn clearly is not.

Even large amounts of physics will NOT cause lag, as long as you use correct coding routines. Also not using 5 billion 400 face brushes in your map might also help.

I will say that someone did have 600,000 active polygons on screen at once with the HL2 leak[100 buggies]...and each buggy even still had its shadow rendered, all running at 30 FPS.

 

[marksmanHL2 :)]

Polykarbon: Interesting read mate. And nice to know

 

[KurtCobain]

Don't know if this has been said , coz well i culdnt b bothered to read it all...but...


...The pyshics in MP will be both server side and client side, almost 50/50
Big Objects that can be used for cover etc will be server side and smaller , less importance objects will be client side (i think thats right way round)

Again sos if its been said b4

 

[Farrowlesparrow]

Not sure if thats allowed to be talked about but since this isn't my area i can't do anything.

Interesting stuff though...I suspect the multiplayer will be improved come release as well.

 

[Polykarbon]

Well said, although logically there are only a few things that would need to be client side--in stock multiplayer anyway. The larger the objects the better, believe it or not.

Cheers,

PK

BTW--If I violated anything, please delete it. I apologize for speaking of the illegal stolen build.

 

[Beserker]

In HL when you made maps you would make boxes 2 ways:
Select pre-made from the list or make your own and texture them.

In hopefully soon-to-be-realeased SDK would the pre-made objects have physics already put into them? And if you make your own would you have to set your own weight etc. to that object?

SDK is going tobe easy but the new engine definetly brings some headaches.

 

[Lethal8472]

Valve has said that pre-made objects will already have their weight, buoyancy, etc. coded into them. Objects that you make will be automatically coded with the proper specs according to the material you used to make them, but you can probably adjust them as needed.

EDIT: Spelling