Isometric projection - Definition and Overview

Isometric drawing of a TV

Isometric projection is a form of orthographic projection, or more specifically, an axonometric projection. It is a method for the visual representation of three-dimensional objects in two dimensions in which the angles between the projection of the x, y, and z axes are all the same, or 120°. For objects with surfaces that are substantially perpendicular to and/or parallel with one another, it corresponds to rotation of the object by +/- 45° about the vertical axis, followed by rotation of approximately +/- 35.264° [= arcsin(tan(30°))] about the horizontal axis starting from an orthographic projection view that is perpendicular to a face of the object.

Isometric projection can be visualized by considering the view of a cubical room from an upper corner, looking towards the opposite lower corner. The x-axis is diagonally down and right, the z-axis is diagonally down and left, and the y-axis is straight up. Depth is also shown by height on the image. Lines drawn along the axes are at 120° to one another. The term isometric comes from the Greek for "equal measure.", which reflects that the scale along each axis of the projection is the same (this is not true of some other forms of projection). Isometric projection is one of the projections used in drafting.

Computer and video games

Isometric projection is used in many computer and video games. Some notable ones include:

• Alien 8: Platform game and one of the first games to use isometric projection.
• Close Combat series: Tactical RTS games.
• Clue: Murder at Boddy Mansion: the computer game version of the board game Clue.
• Diablo and Diablo II: Dungeon-romping RPG games.
• Final Fantasy Tactics: A strategic role-playing game.
• Final Fantasy Tactics Advance: A Game Boy Advance strategic role-playing game based on the first Tactics game.
• Front Mission (the first game in the series): A strategic role-playing game.
• Furcadia: A massively-multiplayer online social game (MMOSG)
• Jagged Alliance turn-based, squad tactical.
• La Pucelle: A strategic role-playing game.
• Phantom Brave: A strategic role-playing game.
• SimCity 2000, 3000, and 4.
• Sonic 3D Blast: An action/platformer game.
• Super Mario RPG: A role-playing game.
• StarCraft: Science-fiction RTS.
• The Sims: simulated people controlled by the player.
• Ultima Online: Massively multiplayer online fantasy combat game.
• X-COM: Alien invasion strategy game.
• Zaxxon: Early arcade space flight fight.

External links

• An explanation of Isometric Projection from University of Limerick (http://www.ul.ie/~rynnet/keanea/isometri.htm)
• Explanation and tutorial on drawing in Isometric from the University of Hertfordshire (http://www.ider.herts.ac.uk/school/courseware/graphics/3d_graphics.html)