Dimension/Depth/Space & Katamari

Developed by Namco Bandai, Katamari Forever is a PlayStation 3 game that has a complete environment within itself. To navigate through the game, a sense of dimension and size is necessary. Relative size is important to play the game because the objective is to roll up similar-sized objects into a ball. The more you roll up, the larger objects you can gather. Relative size also has a role in depth perception in the game. In the screenshot, the signs on the street appear smaller and smaller, a two-dimensional cue that they are receding into the background, becoming further and further away. The people in the screenshot also show signs of relative size. They look smaller as they recede into space. Linear perspective is also put into use. The lines for the little street or sidewalk curve together into the upper left side of the screen, into a vanishing point. More converging lines can be seen at the buildings at the top. Their base lines and other construction lines converge towards where the curving sidewalk lines are going. Another cue is overlap. The signs on the road are overlapping each other. Some look to be in front, while others behind. The rolling ball in the center of the screen is overlapping the objects on the blanket. The effect reinforces a sense of depth as it puts objects in front or behind each other. Finally, the game also simulates a texture gradient. At the bottom of the image, the white spots of the street's texture are spaced out and large. When the eye travels upwards, the texture starts becoming smaller and the white spots begin disappearing. The gradient's loss of detail reflects the human nearsighted vision, where objects are clearer when close, and blurrier when far. With the use of these depth and size cues, Katamari Forever creates a virtual world for players that seems tangible.

image source: http://ps3.ign.com/dor/objects/14333801/katamari-damacy-tribute/images/katamari-forever-20090814033434654.html
more info: http://www.katamariforever.com/