CPU PhysX?

[Strawberry]

So why can't I just run PhysX on my CPU instead, without losing functionality?

Does PhysX really stress so much that a 4 GHz quad can't handle it?

 

[Strawberry]

Depends on quite a few things... if your just chucking around 10s of RBs and a handful of ragdolls then the CPU could handle it fine, if the CPU was just doing physics and no other game processing then it could handle quite a bit of physics fine... in a scenario tho where you have a multi thread capable game thats making decent use of the CPU and the game contains a number of soft body, cloth, fluid, etc. physics effects it would be brought to its knees no matter what current CPU - even the new 12 core ones... whereas a decent GPU could pull it off and still be running 40+fps.

What about UT3 or Mirror's Edge?

Also, are there any modern PhysX-only cards? Getting a whole NVidia card just to have hardware PhysX seems like a bit of a throwaway.

 

[Strawberry]

Ah, I was just interested in that small bit of "Extra Immersion" though. I've read some posts by people that were absolutely stunned when they enabled PhysX when playing, for example, Mirror's Edge - so I thought the game would be 100x better with it on.

Is there a way to force PhysX effects to be used even with no PhysX-capable card installed? I want to see if I can realistically run it on my CPU.

 

[Strawberry]

Throwing around 3000 RB primitives and a few ragdolls in a highly specialised solver is one thing, performance on general purpose middleware physics engine another. Very few studios have the skill, time and resources to create their own highly specialised physics solver.

A fast quad core can quite easily handle far more rigid body physics and simple ragdolls than we have seen in most games to date - even PhysX titles. A fast quad core absolutely can't handle the physics workload in a proper game environment with a reasonable level of both rigid and soft body physic effects (a GPU can) - which no one would say didn't enchance the game considerably if they actually played such a game but won't happen because no developer wants to narrow down their potential market that much.

PhysX would certainly be interesting in a fully-sandbox environment where nearly every object has physics, but it seems like there are no games to date that actually use this.

Note: Interesting enough, the most physics-heavy game I have is Oblivion, and it's only optimized for running on a single core, which a 1 GHz can easily play at 30+fps, and my current setup eats it up. Every single object has physical properties in Oblivion, even if they aren't 100% realistic, but collisions etc. are very convincing, especially if picking something up and dragging it against some other object.

This is only rigid body though.

 

[Strawberry]

As for suggesting phsyx is capable of so much more earlier up, horse crap, the design and things that can be done are based on the designers thoughts, physx is merely a way to calculate things after the design. Everything must be designed, every breakable object in a game must be designed to be breakable, and this will always take FAR longer than making the same object thats not breakable.

I wouldn't readily agree with that. We've seen more than enough techdemos of realistically self-breakable objects that require no user input (Crysis, The Force Unleashed, etc), instead using their own physical properties to decide where to break. Even if this would be too computationally expensive, such things could be pre-computed.