Invisible wall

"Invisible walls" redirects here. For the video blog and podcast, see GameTrailers § Invisible Walls.

An invisible wall or invisi-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 gameplay 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 an area containing nothing at all; or the user may find themselves reappearing on the opposite side of the gameplay area. Alternatively, a run-time error could occur.

Examples

• Horace Goes Skiing features walls on all four sides of the first screen.
• In the 3D First person shooter game Doom, using a "no clipping" cheat enables the player to freely move around the visible part of the current map and beyond it, at least up to the limit imposed by the coordinate system of the game itself. Once beyond the boundary of the current map, 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 PlayStation 1 game Spyro the Dragon, invisible walls are presented as part of the dragon world's technology, being marked by equally spaced podium-like structures that are implied to project the wall like a fence and match the surrounding architecture. Walking into the wall will knock Spyro back, accompanied by an electric "zap" sound and a blue ripple effect where contact with the wall was made.

• In several MechWarrior series installations the mission area isn't blocked by any kind of obstacles, however the boundary is marked on the radar and approaching this boundary will call an audio warning. Ignoring the message and leaving the mission area will result in failure to complete the mission.

• 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 wall. 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 to 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, players can enable a cheat known as "God" and fall off buildings and explore some of the area, but with multiple invisible walls.

• In the video games GTA Vice City and GTA Vice City Stories, there are invisible walls that bound the game's map.

• In "Destroy All Humans!" if the player goes past the edge of the "invasion zone", Orthopox warns the player that they are out of range. Going any further will cause him to automatically pull the player back to the mothership.

• Mercenaries: Playground of Destruction features a "restricted zone" outside the border of the map. The player will be attacked by air units for entering the restricted zone.

• Halo 3 uses several invisible wall devices.

• 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. Unlike some implementations of "invisible walls", there is no fence or other barrier to make the restriction believable.

• In Flatout there are many invisible walls that seem to have scenery painted on them.

• In World of Warcraft, invisible walls are usually presented to the player as a slope that is too steep to climb. In earlier versions of the game, the original pre-BC "vanilla" world was not flyable. Slopes and invisible walls prevented the player from exploring areas of the map which did not have rendered terrain.

• In Total War (series), in the tactical mode, the map is about 9 times larger than the playable area in the center, giving the illusion of vast distances. The border becomes visible only in immediate proximity of the camera. Escaping units can cross it while leaving, and arriving units, while emerging in the battle. Units outside the border can neither be targeted by the enemy nor controlled by its owner.

• In the Supreme Commander games, Anno 2070 and several other strategy games, some missions can be fragmentized and completed in a number of steps, whereby each step will be marked by moving the invisible walls, increasing, reducing or moving the playable area.

• In Borderlands, by leaving the border of the map the screen displays gun turrets locking-on to the player if they stay in their line of fire for more than 20 seconds, thus acting as an "invisible wall".

• In Journey, invisible walls are represented as impassable winds which knock the player back.