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PhysX on ATI Cards
I"m going to buy a new computer, and I'm wondering if the physics engine (since it's based on NVidia PhysX) will work properly on an ATI card. I couldn't really tell if PhysX is just augmenting the existing Unity physics engine, or if PhysX IS the Unity physics engine.
So does anyone know if I can still access most of the physics engine on an ATI card?
Thanks,
You don't "not get" anything with PhysX as an ATI user. Everyone on every computer runs PhysX the exact same way; through their processor. This is true of every game you will make in Unity.
Also as an aside, I feel that it's pointless for Unity to include PhysX if it's not going to allow GPU support, as GPU support is currently the only thing that makes PhysX a better solution than similar solutions such as Bullet and others. That being said, I understand a lot of gamers have ATI cards, but just as many have an Nvidia card and it would be nice if for those of us who have one, we could at least provide the option for ourselves and players to have enhanced PhysX simulations. Right now, it's not feasible to include things like cloth in a finished game unless it's the size of a few sheets of paper because of it being on the back of our processors. (And it's part of why I shake my head when people say "Hey, let's ask for fluid PhysX!" Good luck running that on your processor. :) We need GPU PhysX before that should even be an option.)
Ultimately, we can only hope the Unity $$anonymous$$m will do the right thing here, as despite this being a pretty prevalent demand on the Unity $$anonymous$$gestion site, it still hasn't even come under review yet.
So, in lamen's terms... wikipedia posted the following statement:
Built-in support for Nvidia's (formerly Ageia's) PhysX physics engine,[18] version 2.8.3 (as of Unity 3.0) with added support for real time cloth on arbitrary and skinned meshes, thick ray casts, and collision layers.
What does this mean to people that are starting from square one (i.e. no experience but want to learn this). Will it make a difference (at any level) whether we use an nVidia or ATi card?
Thanks for your help!!!
@mloewen: don't post comments as answers. Anyway, as I said in my answer, physics is totally software-based, the GPU is irrelevant.
Answer by Eric5h5 · Jul 24, 2011 at 05:37 AM
Physics is totally software-based, including on nVidia cards...it would certainly be mentioned if Unity wouldn't run on most graphics cards (not to mention an incredibly boneheaded business decision--remember that Intel graphics account for a substantial percentage, it's not just AMD/nVidia).
@VivekSridhar: I don't know what you mean by "without PhysX". There isn't any "without PhysX"; Unity is the same on all graphics cards. It doesn't use hardware acceleration for physics at all, but there is nothing missing.
Oh okay, I think I get it. PhysX just lets the GPU take care of the physics simulation ins$$anonymous$$d of the CPU, and that doesn't happen on non-NVidia GPUs
Correct, but in Unity, even Nvidia cards don't get to use the GPU for PhysX because of (in my opinion) poor implementation.
@BerggreenD$$anonymous$$: Yes, it's true. Physics in Unity is software-based. It does not utilize any nVidia GPUs, and it does not have any hardware support at all. It probably never will, unless there's a cross-platform solution someday.