PhysX, the physics engine used in many first and third-person games to make models and scenery move more realistically, will be coming to Planetside 2 and observant players may already have seen a GPU physics option greyed out in their game settings. However, if you have the nous to open up one of the games .ini files in Notepad and tweak just two lines of the configuration, you can turn it on right now.
Find your useroptions.ini file, which should be in the Planetside 2 folder within Steam (X:\Steam\steamapps\common\PlanetSide 2) and open it up in a text editor. Look for the second section of settings, which will be called [Rendering].
Add these two lines to the end of it:
And you're away. The physics are entirely client-side, so it's up to you if you'd rather include them or not based on performance or personal preference, but they shouldn't take much of a toll on your frame rate. Here's some footage that will give you an idea of the difference that Physx makes: