Invisible wall

An invisible wall is a video game term for a boundary that limits where a player can go in a certain area, but doesn't appear in-game as any kind of visible obstacle, or as an obstacle that in reality could easily be bypassed, such as a mid-sized rock or short fence. In 2D games, the edge of the screen itself can form an "invisible wall", in that a character in play may be prevented from travelling off the edge of the screen. In 3D games, invisible walls are used similarly to prevent a player leaving the game-play area. This is often done in preference to using a more visible boundary, as this can reduce the realism of the environment.

Related errors

In some games, errors in the programming, or use of computer game cheats can result in the wall becoming penetrable. If a user passes through the wall, they may enter an area of the game not intended for their use, for example an area containing unused items or portions of a level; or the user may find themselves reappearing on the opposite side of the game-play area. Alternatively, a run-time error could occur.

Examples

• In the 3D First person shooter game Doom, using a "no clipping" cheat enables the player to freely move not only around the visible part of the current map, but even beyond it, at least up to the limit imposed by the coordinate system of the game itself, which is the only true "invisible barrier". In the latter case, the first person perspective display becomes corrupt, while the map mode still correctly tracks the player's movements.

• In the vertically scrolling NES game Front Line, due to a programming glitch the player can continue moving sideways off the screen beyond the intended "playfield" area, causing the graphic tiles to become corrupted and enabling the player to slip past most enemies, who won't follow him into the glitchy "void". The actual "invisible wall" is not where the player is (normally) supposed to be playing, but extends farther to the left and right sides of the screen.

• In the game Battlefield 1942, while a player is normally prevented from exiting a map's boundaries with a timed death penalty, in certain circumstances those barriers can be violated (e.g. by using the free flying camera mode, using an unusually high speed vehicle or finding an unusually "thin" boundary area) and will result in a map wrap-around effect (the player will emerge on the opposite side of the map).

• In the Tony Hawk Pro Skater series, large indoor and outdoor areas are featured. While indoor areas have logical walls to confine the player, outdoor areas often use an invisible line. Rather than an actual barrier, the skater will 'bail' from his or her board, an error message is displayed, and the skater will be reset at a certain point.

• In the game Grand Theft Auto III, many large buildings are incomplete and do not have a roof. These are normally not accessible, but through the use of cheats, the player can reach these spots. When the player goes into the top of one of these roofless buildings, everything will spin around them, and the city will appear upside down momentarily while the player is falling towards it. When it all ends, the player will be back on the streets below.

• In the game Max Payne, if the player enable a cheat known as "God", he/she will never die even if shot multiple times or after falling from a high building. Once the player falls off a building in-game, the player can explore some of the area, but when the player goes too far, there are multiple invisible walls. At the far end, there are New York City buildings.

• In the video games, GTA Vice City and GTA Vice City Stories when travelling on a boat, once the player goes past the limit, they will hit an invisible wall or turn back to the direction from which they came.

• In "Destroy All Humans!" if the player goes past the edge of the "invasion zone", Orthopox warns you that you're out of range. Going any further will cause him to automatically pull you back to the mothership.
  • In contrast, since Orthopox was killed in "Destroy All Humans! 2", a transparent, blue forcefield prevents you from going off the map.

• Halo 3 uses several invisible wall devices.
  • On some multiplayer maps, automated devices will kill players who leave the boundaries of the playing area. Players who die in this way are considered to be "killed by the Guardians."
  • All maps contain solid barriers preventing players and player-occupied vehicles from leaving playing areas. Other items can easily penetrate these barriers.
  • If a player manages to defeat the barriers, the player is pushed back into the map.
  • If a player manages to stay outside the boundaries for a few seconds, the player is killed, also "by the Guardians."
  • On some maps, players who leave the playing area in aircraft hit a death barrier. Players dying in this way are penalized in the same way as players who fall into a bottomless pit.

• The Elder Scrolls IV: Oblivion and Fallout 3 features a variation of the invisible wall, when the player reaches the boundaries a message is displayed that says "You cannot go that way, turn back" and the player is prohibited from going any further.
  • If the player walks towards the end of the playable map the scenery, such as grass and trees, stops being drawn. If the player persists the floor eventually falls away from under the player. This is reached easily using the game's "No Clip" feature.

• In the games Star Wars Battlefront and Star Wars Battlefront II, if the player attempts to go outside of the boundaries of a map, a message is displayed that says "Leaving Battlefield". If the player attempts to go further the player's character is killed.

• In Flatout there are many invisible walls that seem to have scenery painted on them. These walls are also easy to go over.

• In Spongebob Squarepants: Battle for Bikini Bottom, there are many areas that, in the absence of invisible walls, a player could go out of boundaries (i.e., Sand Mountain, Spongebob's Dream), but this is stopped by a large hand catching the player. However, in some areas, the "sea floor" can be walked on, and eventually you can fall out of the world.

• In Borderlands, leaving the area through boundaries will result in death and a monetary fee for respawn. Some instances are explained with a voice/visual warning and the attention of sentry turrets. Getting past this boundary (in T-Bone Junction) by switching vehicle seats midfall will allow the player to move around outside.
  • Scenery is not solid (though the ground is), and falling off the ground will result in the player falling for a few minutes. The player is eventually killed off and respawned, though without a New-U fee.

• In free-roaming games like Just Cause 2 and Crackdown, the invisible wall is not easily definable. In the latter game, the player can swim a certain distance our and get "yanked" back, shown by the sea surface texture suddenly changing. In the former game, the player can hit the invisible wall and keep swimming, not aware that they're swimming in place.