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Before shadowing, characters and objects in 3D games appeared to lack grounding, floating along the surface of the terrain. Similarly, particle effects are used by developers to connect players to the game world and show that the character under the player's control is physically affecting, or being affecting by these other elements. Without particles, scene elements won't interact with one another or the world. As an example, imagine a mini-gun that cut down enemies without any muzzle flash, ejected casings, smoke, or steam from the red hot barrel. With particles in a non-PhysX accelerated title the aforementioned items would appear in a uniform fashion – the casings would always spew out in a particular arc regardless of the character’s stance or movement speed, and the smoke and steam would be static.

By incorporating PhysX Particles, not only can the developer include significantly more effects, they can also simulate those effects accurately. In the case of Madness Returns, smoke from Alice’s chain gun dissipates and is manipulated by the environment realistically, and the particles and embers from her pepper-themed projectiles accurately cast around the weapon before making their descent towards the ground. In general, by incorporating simulated particles Alice’s attacks become far more visceral and the world more immersive, and even though the previously mentioned goop fluid effect can emit up to 10,000 particles alone, there is more than enough horsepower left in the GPU to simultaneously accelerate thousands more. Additionally, these particles conform to the same collision standards as the goop particles, meaning they collide and interact with the environment and objects accurately, and therefore do not move or clip through scene elements, or vanish through the floor as in other games.

As Alice strafes to the right the smoke from her Pepper Grinder Gun spreads across the environment and is subsequently dissipated as she moves left once more. See this particular example in action in the video on page one.

As you can see in the accompanying video and images, the shields of Mad Caps shatter realistically into many pieces, smoke pours from Alice’s Pepper Grinder gun, and showers of debris litter scenes when enemies are destroyed. More subtly, particles are used for leaves in forests, bubbles in whimsical areas, dust motes, floating embers, and to enhance the feathers, butterflies and smoke that appear when Alice double-jumps.

With PhysX enabled there are significantly more objects surrounding Alice as she performs a double-jump, each of which will float away realistically.

A Mad Cap’s shield disintegrates into hundreds of pieces and particles after several blows from Alice’s deadly Hobby Horse.

Enemies, like the Mad Cap above, emit extra particles during their attacks and explode into extra pieces when clobbered to death by Alice, Alice’s own physical attacks appear more deadly and powerful with the addition of extra particles, and explosions and magically-powered barriers are enhanced further. Almost every aspect of Alice: Madness Returns has been augmented with extra PhysX particle effects, and to detail each and every one would take many thousands of words – instead, check out the many examples below.

In this side-by-side example, the same object is destroyed with and without PhysX enabled. As is clear to see, there are significantly more particles with PhysX enabled, each reacting and colliding correctly.

In a scene filled with goop, the Snarks create several thousand more particles as they make a dash for Alice. In addition, Alice’s Pepper Grinder Gun is spewing embers and smoke as she moves.

Bubbles, mostly used to increase ambience, are in this case used to enhance an explosion in a particularly unusual environment. Note the extra particles emanating from the explosion, too.

The Executioner’s scythe emits hundreds of extra particles as it clips the ground during a chase scene.

Alice’s double-jump ability can also be utilized to glide between gaps in the world’s geometry. As she glides, the particles, smoke, feathers and butterflies spread out and move realistically according to Alice’s velocity and direction.

This particular environment may not be deformable, but Alice’s Hobby Horse does emit hundreds of particles when it strikes the stony surface.

A Mad Cap battle results in the release of motion-blurred particles in addition to debris from the Mad Cap itself.

As the enemy fires a projectile at Alice it misses, striking the goop instead, causing it to react, splash, and be dragged further from the main pool. Note also how the goop has attached itself to Alice’s shoes after she stepped briefly through it. Additionally, embers can be seen emanating from the enemy and Alice’s Pepper Grinder Gun, which as always is spewing out realistic smoke as it fires, and extra particle effects can be seen emanating from the projectile’s explosion as well.

A close-up view of the Pepper Grinder Gun’s particle-driven smoke and ember effects.

In an ice environment filled with debris, a Snark attacks Alice. As it dashes towards her, it creates a path through the debris, realistically pushing it away to the sides. Additionally, the scene is filled with smoke and numerous butterflies, signifying that Alice has just used her teleport ability to evade the Snark. With PhysX disabled the ground is completely clear of debris and far fewer butterflies appear.

Alice puts the finishing blows on the Snark, creating yet more particles and shifting the debris even further.

Continue to page three to read about the use of APEX in Alice: Madness Returns >>