Projection from 3D to 2D is defined by straight projection rays ( projectors ) emanating from the ' center of projection ', passing through each point of the object, and intersecting the ' projection plane ' to form a projection.
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Perspective Projections p ( x,y,z ) z y Projection plane p s ( x s ,y s ) C d By similar triangles: p ( x,y,z ) z x Projection plane p s ( x s ,y s ) C d
The direction of the projection makes a 63.4 degree angle with the projection plane. This results in foreshortening of the z axis, and provides a more “realistic” view.
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Oblique Parallel Projections x y (x s ,y s ) (0,0,1) P Consider the point P: P can be represented in 3D space - (0,0,1) P can be represented in 2D (screen coords) - (x s ,y s )
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