Physics - PhysX?

[Ben_uk 24]

Ive heard the devs state that they will incorporate "physics" in a upcoming update. However I am confused as to whether it will be just their own "physics engine" or if it will be "nVidia PhysX"...? Anyone know?

[SmashT 10907]

They are using the Bullet Physics SDK afaik

http://bulletphysics.org/

[Element47 2481]

fun anectode - when i first read about it - i think Dean was explaining something in a reddit reply - i thought they use military ballistics simulation from BI, developed for 'bullets' - only later i realized that 'Bullet' is the name of a complete (and open-source) physics library

[Ben_uk 24]

I take it that just runs on the CPU then?

[Etherious 907]

I take it that just runs on the CPU then?

No, it's a completely different thing from what your thinking of. It's nothing having to do with graphics and such, it has to do with actual physics like gravity, inertia, etc... So, for example you can throw a can opener and it will be thrown with all the physics stuff happening to it. (I was never good at Physics lol)

[wirher 8]

I take it that just runs on the CPU then?

Yes, because who will install nvidia card on server?

[king_of_the_beans 92]

The Physics from ARMA 3 look great, not always realistic but great.

[BruceDoh 1]

I take it that just runs on the CPU then?

Generally the way physics works in networked games, is that the server handles the "real" physics. Each client will also simulate the physics, however it will be constantly receiving updates from the server, which override the physics the client has done.

 

The reason it is done this way is to give the illusion of zero latency, while making the server "authoritative", meaning the server's data is more highly valued than the client's data, which could be tampered with by cheaters. Client side physics simulations make it so when you perform an action, you don't have to wait for the message to go to the server and relayed back to you before seeing the results. Having the server simulate the physics means that everyone should see approximately the same thing regardless of how out of sync they are.

 

It does get quite a bit more complicated than that for games like this, or first person shooters, where it would be a bit unfair for a player to aim perfectly, and not hit the player because they are out of sync with the server. A player shouldn't have to compensate for lag when aiming. Basically there is a lot of give and take, and most solutions to these problems introduce new problems. It's basically a balance between making a consistent simulation for all players, making what the player sees as close as possible to what the server is doing, reducing rubber-banding, and reducing the ability of players to cheat.

 

So to answer your question: Yes, the physics run on the CPUs of both the client and the server. Although rarely games will leverage the GPU as well, with most of the work being done server-side, this is unlikely.

Edited April 30, 2014 by BruceDoh