Ben Sun · 02-09-2009 · Category: Guides

Mirror's Edge PhysX Effects

Mirror's Edge really takes full advantage of the PhysX effects available on NVIDIA video cards. You can also play the game with PhysX effects using the CPU on non-NVIDIA cards but the performance will suffer as there isn't a dedicated card for PhysX being used. The game makes use of cloth, particle, glass smoke, and wind effects throughout the game.

PhysX cloth

Non PhysX cloth

Cloth effects are used throughout the game. There are banners that ripple with the wind, flags that wave when in motion, curtains that move when PhysX is turned on and more throughout the game. These all interact with the character or the environment. For example, there's a helicopter that hovers through much of the game. This helicopter has rotors which cause the construction tarp to ripple. The flags can be shot at and if you get entangled in a curtain it can be dragged across the floor by the character.

PhysX Glass

Non PhysX Glass

Persistent Glass

Glass effects are hard to simulate. Without PhysX some shards of glass in the game are broken out of the glass then disappear. With PhysX enabled, the glass interacts with the environment and is persistent (i.e. doesn't disappear after a second). Further there are many shards of glass when PhysX is enabled which are not present when it is disabled. When PhysX is enabled glass has physical form in other words, it can be kicked or blown by the wind. Another interesting effect in the game is when glass lands on top of enemies killing them.

PhysX Smoke

Non PhysX Smoke

Smoke can be used in a game to enhance the atmosphere of the game. Games without physically simulated smoke tend to have alpha blended polygons with pre-scripted motions. Mirror's Edge uses physically simulated smoke in areas of the game. In Mirror's Edge when you move through smoke you leave a trail. In the games there are many times that the helicopter is flying over smoke from a chimney or vent. The rotor wash from the helicopter causes smoke to move away as it flies over it.

PhysX Wind

Non PhysX Wind

Wind is an ever-present part of the game. As stated earlier, the cloth in the game moves according to the wind whether it's from a helicopter, or from gunfire or other wind source. Wind from a train can cause banners to sway in the subway. Helicopters stir up dust and debris. This is one of the benefits of having physics an integral part of the game as normally the helicopters and trains would not have an effect on the debris.

Contents

1. Introduction
2. Mirror's Edge Story
3. Mirror's Edge Game play and Controls
4. Mirror's Edge Graphics and Sound
5. Mirror's Edge PhysX Effects
6. Mirror's Edge System Requirements
7. Conclusion