Editing 2.5D (section)

===Scaling along the Z axis===
In some games, sprites are scaled larger or smaller depending on its distance to the player, producing the illusion of motion along the Z (forward) axis. [[Sega]]'s 1986 video game ''[[Out Run]]'', which runs on the [[Sega OutRun]] [[arcade system board]], is a good example of this technique.

In ''Out Run'', the player drives a Ferrari into depth of the game window. The palms on the left and right side of the street are the same [[bitmap]], but have been scaled to different sizes, creating the illusion that some are closer than others. The angles of movement are "left and right" and "into the depth" (while still capable of doing so technically, this game did not allow making a U-turn or going into reverse, therefore moving "out of the depth", as this did not make sense to the high-speed game play and tense time limit). Notice the view is comparable to that which a driver would have in [[reality]] when driving a car. The position and size of any billboard is generated by a (complete 3D) perspective transformation as are the vertices of the poly-line representing the center of the street. Often the center of the street is stored as a spline and sampled in a way that on straight streets every sampling point corresponds to one scan-line on the screen. Hills and curves lead to multiple points on one line and one has to be chosen. Or one line is without any point and has to be interpolated lineary from the adjacent lines. Very memory intensive billboards are used in ''Out Run'' to draw corn-fields and water waves which are wider than the screen even at the largest viewing distance and also in [[Test Drive (1987 video game)|''Test Drive'']] to draw trees and cliffs.

''[[Drakkhen]]'' was notable for being among the first [[role-playing video game]]s to feature a three-dimensional playing field. However, it did not employ a conventional 3D game engine, instead emulating one using character-scaling algorithms. The player's party travels overland on a flat terrain made up of vectors, on which 2D objects are zoomed. ''Drakkhen'' features an animated day-night cycle, and the ability to wander freely about the game world, both rarities for a game of its era. This type of engine was later used in the game ''[[Eternam]]''.

Some mobile games that were released on the Java ME platform, such as the mobile version of [[Asphalt Urban GT|Asphalt: Urban GT]] and [[Driver: L.A. Undercover]], used this method for rendering the scenery. While the technique is similar to some of Sega's arcade games, such as [[Thunder Blade]] and [[Cool Riders]] and the 32-bit version of [[Road Rash (video game)#CD-based versions|Road Rash]], it uses polygons instead of sprite scaling for buildings and certain objects though it looks flat shaded. Later mobile games (mainly from Gameloft), such as [[Asphalt 4: Elite Racing]] and the mobile version of [[Iron Man 2 (video game)|Iron Man 2]], uses a mix of sprite scaling and texture mapping for some buildings and objects.