Movement and Motion

http://portalkh.files.wordpress.com/2010/08/shipalso.jpg

The Image above is from a part of the video game Kingdom Hearts, where players have to navigate a ship through a 3D environment while dodging obstacles and shooting enemies.  The rout the ship must take from the beginning of the level to the end of the level is a strate line but the 3D obstacles and enemy ships that the player must dodge means that the player needs to be able to move all over the path.  This presented a challenge to the designers of the level because they had to decide how to allow the player to navigate vertically and horizontally through the space as well as forward, without getting disoriented and losing track of where the path is.  In order to solve this problem, the game designers made it so the game camera never moves.  It always stays in the center of the path and everything the ship flies towards simply looks like it is al moving backwards.  while the camera stays in place, the ship is free to move horizontally and vertically on the screen, allowing it to dodge the obstacles that are flying towards the camera and the ship.  The motions of all the obstacles moving toward the camera gives the illusion that the ship and camera are flying forward through space.  

http://upload.wikimedia.org/wikipedia/en/thumb/e/eb/MarioPArtyDS.jpg/220px-MarioPArtyDS.jpg

This is a screen shot of a mini game from Mario Party DS.  In this game, the player's character is on a conveyer belt that is moving towards the camera.  The conveyer belt is covered in food that act as obstacles that players must run around.  If a player does not successfully get around an obstacle, they will fall off the end of the belt and lose the game.  This game is very similar to the game addressed above however simply letting the character move left and right would not work here.  They players would not have enough time to navigate around some of the bigger obstacles if they were confined to a set depth away from the camera like the ship is.  To solve this problem, the game designers allow the player to move there characters forward and backward through space rather than just left and right or up and down.  This allows the players to move father away from the edge of the conveyer belt, which gives them more time to successfully dodge the obstacles and eventually wint the game.