Is this for current GPUs or the new DirectX 10 cards?

Edit: never mind, helps to watch to the end

The reason it's so effective when running on the GPU is that the GPU is optimized for the types of calculations that a physics engine requires. (Except instead of static geometry and transformations, it's just doing dynamic positioning and collision detection, which is an extension of what a GPU was made for.)

Also, since the physics calculations are a lot simpler than the graphics calculations (it's easy to calculate a ball bouncing on the ground, but harder to calculate what a surface with normal maps, specularity, and a complex mesh would look like) this wouldn't necessarily require a very powerful card to deal with the calculations. An old Voodoo 5 would probably have no problem doing these calculations. Where it gets difficult is when you get a lot of objects, which would definitely require a more powerful card, especially if you want it to draw your pretty graphics as well.

An important note: while the new DirectX 10 (or should I say Direct3D 10) cards definitely have the power to do the more complex physics calculations, it doesn't have anything to do with DirectX. (A lot of people I've spoken to recently seem to be under the impression that DirectX 10 = "OMG L33T PHYSICS!")

Kewl.

*dead

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