Zero-Point Energy Field Manipulator
Encyclopedia
A gravity gun is a concept in video games, particularly first-person shooter
s using an advanced physics engine
, whereby players can directly manipulate objects in the world, often allowing them to be used as projectiles against hostile characters. A gravity gun is usually manifested as an in-game weapon, available from the player's inventory or weapon selection. The concept was first popularized by the gravity gun found in Valve Software's
Half-Life 2
; however, a similar concept was used by developers id Software
during the production of the earlier game Doom 3
, eventually leading to the introduction of a physics-based weapon in the expansion pack Resurrection of Evil
. Later games have been influenced by the success of these physics-based weapons, adopting their own styles of comparable abilities or weapons.
Valve Software's Half-Life 2 made significant use of physics in the game, powered by Havok physics engine
. Although the player can pick up and throw objects early in the game, this ability is somewhat limited in scope. Around a quarter of the way through the game, the player acquires the gravity gun, properly named as the "zero-point energy field manipulator
". Alyx Vance
explains that the gravity gun is designed for handling hazardous materials, but is mostly used for heavy lifting. She explains to Gordon that she once found it useful "for clearing minefields
". The gravity gun significantly increases the player's ability to manipulate objects in the game. Like most other weapons in the game, the gravity gun has two trigger functions. The primary trigger causes the gun to emit a small discharge which emits energy to the targeted object. The distance which the object is forced is dependent on its weight and distance from the gun. The secondary trigger attracts the targeted object to the gun and holds it in midair a few inches away, negating its weight and allowing the player to carry it with them. Using the secondary trigger again will drop the item, while the primary trigger will launch it with considerable force.
By combining these functions, players can use the gravity gun to scale barriers and obstacles, create cover against enemy characters, or launch the objects at enemy characters, causing them considerable damage. Certain types of objects, such as saw blades, fuel barrels and hydrogen tanks are intentionally designed by Valve to be used as "gravity gun ammunition". The gravity gun, however, cannot manipulate heavier objects and enemy characters until the late stages of the game, when the device becomes temporarily infused with dark energy
meant to destroy it.
The gravity gun was very well received by critics, who considered it one of the defining features of Half-Life 2s entertainment value. Planet Half-Life calls the gravity gun "the next level in interactive gaming." Electronic Gaming Monthly describes Half-Life 2s gravity gun as the "thinking man's death tool," which lets players "toy with gravity to kill foes with everyday objects." Call of Duty series
military adviser Hank Keirsey stated that "the weapon is not very practical". He does, however, discuss its historical precedents, further stating that "The ancients learned very early how to use gravity to their advantage — but this usually involved rolling rocks down hills or pouring boiling oil down the castle walls. Those that failed to respect gravity suffered."
Although Half-Life 2 was the first game released to feature a gravity gun, id Software
had previously conceived a similar idea during the development of the earlier title Doom 3
. id Software designer Matt Hooper noted that "we actually used it as a tool throughout development where we'd grab physics objects and place them around the world". The tool was used to create "damaged" rooms in Doom 3; instead of constructing a ruined room, the designers would code a pristine room and use the device to "damage" it realistically. Although used to assist the development of Doom 3, the gravity gun was not implemented in the final game. Hooper explained that "we talked about that quite a few times, but we had such a big arsenal of weapons, and so many other cool things going on, that it was just one of those things that never made it in". However, Nerve Software
revived the code for the weapon five months after the release of Half-Life 2 in Doom 3s expansion pack
, Resurrection of Evil.
The device is noted in the Doom 3 storyline as an "ionized plasma levitator
", created by the Union Aerospace Corporation
for moving hazardous materials and a forerunner to tractor beam
s. Usually referred to as the "grabber", the player obtains the device early on in the course of Resurrection of Evil. The grabber operates differently from Half-Life 2s gravity gun, using only a single trigger function. Once the grabber is aimed at an appropriate object, it locks on, allowing the player to lift the object with the trigger. When the player releases the trigger, the object will be propelled forward with force, turning it into an impromptu weapon. One key ability of the grabber is its capacity to lock on to the fireball projectiles cast by some hostile non-player characters, allowing players to turn the attack against their foe. However, unlike the gravity gun in Half-Life 2, the grabber cannot hold objects for as long as the player wishes; if they wait too long to launch the object, the grabber will start to overload and disengage, dropping the object gently on the ground. Critics often compared the grabber directly with Half-Life 2s gravity gun, some noting that the device was far more combat-focused in operation than the gravity gun; in particular, the ability to turn projectiles cast by enemies against them was praised. However, the grabber was considered somewhat "awkward" to use, requiring a "finesse" that "is rarely something the player has time for in a close-quarters situation".
's Crysis
allows the player to throw objects and enemy characters considerable distances through the use of an experimental nanosuit
.
In other games, however, it can be represented in a different manner. In Arkane Studios
' Dark Messiah of Might and Magic
a psychokinesis
spell allows for similar functions as Half-Life 2s gravity gun, Destroy All Humans!
portrayed a similar gravity usage, known as PK, while 2K Games
' BioShock
displays the concept as a telekinesis plasmid
that the player uses to alter their character's DNA. In EA's third-person horror shooter Dead Space
, the player character acquires a 'Kinesis' module, which allows the player to grab and throw objects similar to Half-Life 2s gravity gun.
First-person shooter
First-person shooter is a video game genre that centers the gameplay on gun and projectile weapon-based combat through first-person perspective; i.e., the player experiences the action through the eyes of a protagonist. Generally speaking, the first-person shooter shares common traits with other...
s using an advanced physics engine
Physics engine
A physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics , soft body dynamics, and fluid dynamics, of use in the domains of computer graphics, video games and film. Their main uses are in video games , in which case the...
, whereby players can directly manipulate objects in the world, often allowing them to be used as projectiles against hostile characters. A gravity gun is usually manifested as an in-game weapon, available from the player's inventory or weapon selection. The concept was first popularized by the gravity gun found in Valve Software's
Valve Corporation
Valve Corporation is an American video game development and digital distribution company based in Bellevue, Washington, United States...
Half-Life 2
Half-Life 2
Half-Life 2 , the sequel to Half-Life, is a first-person shooter video game and a signature title in the Half-Life series. It is singleplayer, story-driven, science fiction, and linear...
; however, a similar concept was used by developers id Software
Id Software
Id Software is an American video game development company with its headquarters in Richardson, Texas. The company was founded in 1991 by four members of the computer company Softdisk: programmers John Carmack and John Romero, game designer Tom Hall, and artist Adrian Carmack...
during the production of the earlier game Doom 3
Doom 3
Doom 3 is a science fiction horror video game developed by id Software and published by Activision. An example of the first-person shooter genre, Doom 3 was first released for Microsoft Windows on August 3, 2004. The game was later adapted for Linux, as well as being ported by Aspyr Media for Mac...
, eventually leading to the introduction of a physics-based weapon in the expansion pack Resurrection of Evil
Doom 3: Resurrection of Evil
Doom 3: Resurrection of Evil is a first-person shooter video game developed by Nerve Software and id Software. It was released for the PC on April 3, 2005, as an expansion pack for Doom 3 and on October 5, 2005, for the Xbox video game console...
. Later games have been influenced by the success of these physics-based weapons, adopting their own styles of comparable abilities or weapons.
Half-Life 2 gravity gun
Valve Software's Half-Life 2 made significant use of physics in the game, powered by Havok physics engine
Havok (software)
Havok Physics is a physics engine developed by Irish company Havok. It is designed primarily for video games, and allows for real-time collision and dynamics of rigid bodies in three dimensions. It provides multiple types of dynamic constraints between rigid bodies , and has a highly optimized...
. Although the player can pick up and throw objects early in the game, this ability is somewhat limited in scope. Around a quarter of the way through the game, the player acquires the gravity gun, properly named as the "zero-point energy field manipulator
Zero-point energy
Zero-point energy is the lowest possible energy that a quantum mechanical physical system may have; it is the energy of its ground state. All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero-point energy, a consequence of their wave-like nature...
". Alyx Vance
Alyx Vance
Alyx Vance is a non-player character in Valve's 2004 first-person shooter computer game Half-Life 2, and its following episodes: Half-Life 2: Episode One and Half-Life 2: Episode Two...
explains that the gravity gun is designed for handling hazardous materials, but is mostly used for heavy lifting. She explains to Gordon that she once found it useful "for clearing minefields
Land mine
A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....
". The gravity gun significantly increases the player's ability to manipulate objects in the game. Like most other weapons in the game, the gravity gun has two trigger functions. The primary trigger causes the gun to emit a small discharge which emits energy to the targeted object. The distance which the object is forced is dependent on its weight and distance from the gun. The secondary trigger attracts the targeted object to the gun and holds it in midair a few inches away, negating its weight and allowing the player to carry it with them. Using the secondary trigger again will drop the item, while the primary trigger will launch it with considerable force.
By combining these functions, players can use the gravity gun to scale barriers and obstacles, create cover against enemy characters, or launch the objects at enemy characters, causing them considerable damage. Certain types of objects, such as saw blades, fuel barrels and hydrogen tanks are intentionally designed by Valve to be used as "gravity gun ammunition". The gravity gun, however, cannot manipulate heavier objects and enemy characters until the late stages of the game, when the device becomes temporarily infused with dark energy
Dark energy
In physical cosmology, astronomy and celestial mechanics, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted theory to explain recent observations that the universe appears to be expanding...
meant to destroy it.
The gravity gun was very well received by critics, who considered it one of the defining features of Half-Life 2s entertainment value. Planet Half-Life calls the gravity gun "the next level in interactive gaming." Electronic Gaming Monthly describes Half-Life 2s gravity gun as the "thinking man's death tool," which lets players "toy with gravity to kill foes with everyday objects." Call of Duty series
Call of Duty (series)
Call of Duty is a first-person and third-person shooter video game series franchise, created by Ben Chichoski. The series began on the PC, and later expanded to consoles and handhelds. Several spin-off games have also been released...
military adviser Hank Keirsey stated that "the weapon is not very practical". He does, however, discuss its historical precedents, further stating that "The ancients learned very early how to use gravity to their advantage — but this usually involved rolling rocks down hills or pouring boiling oil down the castle walls. Those that failed to respect gravity suffered."
Doom 3 grabber
Id Software
Id Software is an American video game development company with its headquarters in Richardson, Texas. The company was founded in 1991 by four members of the computer company Softdisk: programmers John Carmack and John Romero, game designer Tom Hall, and artist Adrian Carmack...
had previously conceived a similar idea during the development of the earlier title Doom 3
Doom 3
Doom 3 is a science fiction horror video game developed by id Software and published by Activision. An example of the first-person shooter genre, Doom 3 was first released for Microsoft Windows on August 3, 2004. The game was later adapted for Linux, as well as being ported by Aspyr Media for Mac...
. id Software designer Matt Hooper noted that "we actually used it as a tool throughout development where we'd grab physics objects and place them around the world". The tool was used to create "damaged" rooms in Doom 3; instead of constructing a ruined room, the designers would code a pristine room and use the device to "damage" it realistically. Although used to assist the development of Doom 3, the gravity gun was not implemented in the final game. Hooper explained that "we talked about that quite a few times, but we had such a big arsenal of weapons, and so many other cool things going on, that it was just one of those things that never made it in". However, Nerve Software
Nerve Software
Nerve Software is an American video game developer that was co-founded by ex-id Software employee Brandon James. Many of the original employees at Nerve were previously employed by Rogue Entertainment, another U.S...
revived the code for the weapon five months after the release of Half-Life 2 in Doom 3s expansion pack
Expansion pack
An expansion pack, expansion set, or supplement is an addition to an existing role-playing game, tabletop game or video game. These add-ons usually add new game areas, weapons, objects, and/or an extended storyline to a complete and already released game...
, Resurrection of Evil.
The device is noted in the Doom 3 storyline as an "ionized plasma levitator
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
", created by the Union Aerospace Corporation
Union Aerospace Corporation
The Union Aerospace Corporation is a fictional conglomerate focused on military-industrial research in id Software's science fiction video game series Doom. The corporation is depicted to be involved in advanced weapons development, biological research, space exploration and teleportation. The...
for moving hazardous materials and a forerunner to tractor beam
Tractor beam
A tractor beam is a device with the ability to attract one object to another from a distance. Since the 1990s, technology and research has labored to make it a reality, mostly at microscopic level. Less commonly, a similar beam that repels is called a pressor beam or repulsor beam...
s. Usually referred to as the "grabber", the player obtains the device early on in the course of Resurrection of Evil. The grabber operates differently from Half-Life 2s gravity gun, using only a single trigger function. Once the grabber is aimed at an appropriate object, it locks on, allowing the player to lift the object with the trigger. When the player releases the trigger, the object will be propelled forward with force, turning it into an impromptu weapon. One key ability of the grabber is its capacity to lock on to the fireball projectiles cast by some hostile non-player characters, allowing players to turn the attack against their foe. However, unlike the gravity gun in Half-Life 2, the grabber cannot hold objects for as long as the player wishes; if they wait too long to launch the object, the grabber will start to overload and disengage, dropping the object gently on the ground. Critics often compared the grabber directly with Half-Life 2s gravity gun, some noting that the device was far more combat-focused in operation than the gravity gun; in particular, the ability to turn projectiles cast by enemies against them was praised. However, the grabber was considered somewhat "awkward" to use, requiring a "finesse" that "is rarely something the player has time for in a close-quarters situation".
Influence on later games
Various later video games have included gameplay features that allow players to use the game's physics to their advantage in combat. In some cases, these are manifested as weapons or devices. For instance, the Aperture Science Handheld Portal Device in Portal displays a limited capacity to move objects around the game world, while CrytekCrytek
Crytek is a German video game company founded in 1999 by three Turkish brothers: Cevat, Avni and Faruk Yerli. Crytek's main headquarters are in Frankfurt, Germany, with five other studios in Kiev, Budapest, Nottingham, Sofia and Seoul. The company is best known for developing the game Far Cry and...
's Crysis
Crysis
Crysis is a science fiction first-person shooter video game developed by Crytek , published by Electronic Arts for Microsoft Windows, and released in November 2007. It is the first game of a trilogy. A separate game entitled Crysis Warhead was released on September 12, 2008, and follows similar...
allows the player to throw objects and enemy characters considerable distances through the use of an experimental nanosuit
Powered exoskeleton
A powered exoskeleton, also known as powered armor, or exoframe, is a powered mobile machine consisting primarily of an exoskeleton-like framework worn by a person and a power supply that supplies at least part of the activation-energy for limb movement.Powered exoskeletons are designed to assist...
.
In other games, however, it can be represented in a different manner. In Arkane Studios
Arkane Studios
Arkane Studios is a video game developer based in Lyon, France. It was founded in 1999, and released its first game, Arx Fatalis, in 2002. Arkane Studios opened an Austin, Texas-based office in July 2006....
' Dark Messiah of Might and Magic
Dark Messiah of Might and Magic
Dark Messiah of Might and Magic, additionally subtitled Elements on Xbox 360, is a first-person action game developed by Arkane Studios and Floodgate Entertainment. Kuju Entertainment developed the multiplayer mode...
a psychokinesis
Psychokinesis
The term psychokinesis , also referred to as telekinesis with respect to strictly describing movement of matter, sometimes abbreviated PK and TK respectively, is a term...
spell allows for similar functions as Half-Life 2s gravity gun, Destroy All Humans!
Destroy All Humans!
Destroy All Humans! is a video game developed by Pandemic Studios and published by THQ. It was released for the Xbox and PlayStation 2 on June 21, 2005. The game is set in the late 1950s in the U.S. and parodies the lifestyles, pop culture, and politics of this time period...
portrayed a similar gravity usage, known as PK, while 2K Games
2K Games
2K is a global developer, marketer, distributor and publisher of interactive entertainment software games. 2K Games is a subsidiary of Take-Two Interactive, which also owns Rockstar Games notable for the Grand Theft Auto series...
' BioShock
Bioshock
BioShock is a first-person shooter video game developed by 2K Boston and designed by Ken Levine. It was released for Microsoft Windows and Xbox 360 on August 21, 2007 in North America, and three days later in Europe and Australia. It became available on Steam on August 21, 2007...
displays the concept as a telekinesis plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...
that the player uses to alter their character's DNA. In EA's third-person horror shooter Dead Space
Dead Space (video game)
Dead Space is a survival horror third-person shooter video game, developed by EA Redwood Shores for Microsoft Windows, PlayStation 3 and Xbox 360. The game was made available on Steam on October 20, 2008...
, the player character acquires a 'Kinesis' module, which allows the player to grab and throw objects similar to Half-Life 2s gravity gun.