Very early on in any production be it film, animation, video game or television, a script is developed. The script to me is the lifeblood of the project. Story teams refer to the script and writers to block out the beat and rhythm of the story using the script as a guide. Casting directors refer to the script to find the perfect and exact person to act or voice the character. Artists from all ends of the pipeline keep the script in mind as they develop characters, backgrounds, colors and moods. Music is orchestrated extract appropriate emotion from the viewer at any given time. Every aspect is meticulously thought out and refined to support the script and the story. There are a few areas in production that are not always thought about or unnoticed, and for good reason. The physics on a project is just as much considered and evaluated as anything else and when done well, it is unnoticed. It is not distracting. Instead physics helps push the narrative of the film.
Because of the interactive nature of video games, physics plays a unique and new role. Blizzard Entertainment takes full advantage of this in their 2012 title Diablo 3. The concept and story of Diablo 3 is pretty simple. Demons have escaped hell and are rampaging through the cities of earth and heaven. It is up to you to put this right. In the early stages of development Blizzard had planned on using the Unreal Engine to handle the physics and initial tests were impressive. But the decision was made that the tools available to them at the time were not capable of bringing their ideas to life. So they set out to create their own physics engine and the result is fantastic. The game feels snappy and responsive. When I swing my axe I can feel the weight and power behind it. Balls of frost and ice freeze enemies and the smash and shattering of their armor into a thousand shards could not be more satisfying I think Blizzard uses physics to engaging and entertain the viewer in three ways: creating a dynamic and responsive destructible world, A “physics style guide” that enforces the playstyle of each class, and The overall exageration of physics for the sake of entertainment.
Soon after the beginning exposition; you’re placed into an old cathedral. You notice loose floorboards, rusted lighting fixtures and crumbling pillars and walls. you click on them and with a swing of the axe your environment comes falling down around you. Your interaction with the environment as you uncover the secrets of these old ruins furthers the immersion of the game. As you fight your way through enemies, pews smash and bookcases fly across the screen. The physics are dynamic and interactive. You are the one causing these effects and the feeling is satisfying. It is worth mentioning that all of these effects do not bare any actual repercussions on the story or the future of your character nor do they change the mechanics of the game in any way. They were not necessary but Blizzard has always had an eye for detail and it’s seen in how the physical world reacts to you and you to it.
As I continue on through now the crypts and catacombs of the cathedral, I begin to notice other clever use of the physics engine. Banners and cloth and hair react to my actions. As I speed by a table, the table cover quivers and my character’s hair drags and overlaps, a clear use of one of the rules of animation, overlapping action. it gives my character a better sense of believability. instead of coming to a dead stop after running, his clothes and hair continue on moving for a brief moment. Corpses of enemies you’ve slain remain on the ground after you defeat them. I remember spending way too much time simply smashing the ground near the corpses with my hammer to watch in awe as the corpses would shift and move acording to how hard and from which direction the blow came from.
Each class within the game feels unique and different. From the brutish Barbarian to the slick demon hunter, physics plays a huge role in how your character moves and feels. I contribute a huge part to the physics behind your characters movements and attacks and even body language. The physics behind each class is hand crafted and taylored to that class and helps reinforce the characteristics of that class. For example, the demon hunter is a bow and dagger wielding assassin. He moves with precise intention never missing a step or swing. He is a calculated and dexterous fighter. The physics behind his motion and attacks are quick and flowing, nimble and deadly. On the other hand is the brutish Barbarian. He wields 2 one handed weapons or 1 mighty weapon like a huge axe or mace. He is the opposite of the Demon Hunter in every way. He relies on his sheer strength and stopping power to demolish everything in his path. When you play as the Barbarian bodies fly in every direction, blood covers the floor and his insatiable recklessness is indiscriminate of anything in his way. An example of how the physics of the game fuels his power is well explained in one of his abilities: Furious Charge.
When performing a Furious Charge ability, the Barbarian makes a beeline charge from one point to the next. There is almost no slow in, nor slow out. He goes at a constant speed smashing everything in his way. These are just two examples of the five playable classes and each one feels unique. Blizzard has used physics to capture the perfect feeling for each one.
Finally the third way Blizzard uses physics to enhance the game is through exaggeration. The physics in the game are believable but not at all realistic. And I think that is a hard thing to balance. For example, if you take an axe to a 50 year old oak tree in real life you might be able to put a few gashes in per swing but it would take very very long time before timber. On the other hand if you take an axe to say, your dorm room fan, you can imagine the kind of damage you’ll do to it with a swift swing. The game is essentially filled with house fans and you’re given a bat with 30 pound dumbbells tapped to either side. Exaggeration comes strongly into play with the mage class. Because magic is not real and we have no real connection or reference to it, the physics team were able to go wild with animation and explosions. However the effects of these spells are still clearly based on real life physics. Fireball explosions act like missile explosions and shattering ice acts like shattering windows they are based on reality but pushed to impossible lengths. Much of the physics make no sense. The ease at which a crusader wields a sword weighing half of his body weight while holding a shield in the other hand is ridiculous but no one questions it and I wouldn't have it any other way because the situation calls for it. In this story the game is all about you. You fighting endless hordes of enemies the story is pushed to absurd realms and so the physics of the game follows as well.
The physics in Diablo 3 is impressive because it is, for the most part, in reaction to the players input. This allows for a deep feeling of strength through your character. Blizzard created an amazing physics engine from the ground up and it is clear that their investment was directed at pushing immersion and gameplay. A world that physically responds to your actions, a physics “style guide” and pushed and exaggerated physics all help the story and immersion and is never distracting.
