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I am reading a book about 3D concepts and OpenGL. The book always talks about world space, eye space, and so on.

  • What exactly is a world inside the computer monitor screen?

  • What is the world space?

  • What is eye space? Is it synonymous to projection?

nbro
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gamdevNoobie
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  • world space is the world matrix ..i.e whole game map or area...while the eye projection is the view point of the object(it can be any view) i.e w.r.t a person or anyother object use in the game – Saad Abdullah Nov 13 '13 at 06:14
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    this question is more suited for http://gamedev.stackexchange.com/ – Necrolis Nov 13 '13 at 07:23
  • @BROY This [Understanding 4x4 homogenous transform matrices](http://stackoverflow.com/a/28084380/2521214) might help a bit – Spektre Jul 13 '15 at 06:31
  • @BROY There's also this answer I wrote on a similar question that includes an example if that helps: http://stackoverflow.com/a/16226282/1122135 – Robert Rouhani Jul 14 '15 at 14:59
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    gamedev's duplicate question: http://gamedev.stackexchange.com/questions/65783/what-is-world-space-and-eye-space-in-game-development – nbro Jan 12 '17 at 15:27

2 Answers2

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World space

World space is the (arbitrarily chosen) frame of reference in which everything within the world is located in absolute coordinates.

Local space

Local space is space relative to another local frame of reference, in coordinates relative to the local frame.

For example, the mesh of a model will be constructed in relation to a coordinate system local to the model. When you move around the model in the world, the relative positions to each other of the points making up the model don't change. But they change within the world.

Hence there exists a model-to-world transformation from local to world space.

Eye (or view) space

Eye (or view) space is the world as seen by the viewer, i.e. all the positions of things in the world are no longer in relation to the (arbitrary) world coordinate system, but in relation to the viewer.

View space is somewhat special, because it not arbitrarily chosen. The coordinate (0, 0, 0) in view space is the position of the viewer and a certain direction (usually parallel to Z) is the direction of viewing.

So there exists a transformation world-to-view. Now because the viewer is always at the origin of the view space, setting the viewpoint is done by defining the world-to-view transformation.

Since for the purposes of rendering the graphics world space is of little use, you normally coalesce model-to-world and world-to-view transformations into a single model-to-view transformation.

Note that eye (or view) space is not the projection. Projection happens by a separate projection transform that transforms view-to-clip space.

nbro
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datenwolf
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You should read this: http://www.opengl-tutorial.org/beginners-tutorials/tutorial-3-matrices/

That tutorial uses term "camera space" instead of "eye space" but they are the same.

jparimaa
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