The following classifies the most common projections used to represent 3D geometry on a 2D surface. Each projection type has a brief comment describing its unique characteristic.
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An oblique projection is a parallel projection where the projecting lines are not perpendicular to the projection plane. The precise projection is defined by two angles
and
 .
Two common projections are:
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For either one of the above projections values of
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Note:
The first two transformations for xp and yp are all that is required to derive the transformation from 3D onto the 2D projection plane. The third trivial) transformation for z illustrates how an oblique projection is equivalent to a z axis shear followed by a parallel orthographic projection onto a x-y projection plane.
The x and y coordinate values within each z plane are shifted by an amount
proportional to the z value of the plane.
(ie: cos()
/ tan())
so angles, distances, and parallel lines in any z plane are projected
accurately, without distortion.
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Cavalier projection
= 45
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Cavalier projection
= 30
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Cabinet projection
= 45
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Cabinet projection
= 30
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