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2.1 Geometric primitives and transformations 43

(a) 3D view (b) orthography

(c) scaled orthography (d) para-perspective

(e) perspective (f) object-centered

Figure 2.7 Commonly used projection models: (a) 3D view of world, (b) orthography, (c) scaled orthography,
(d) para-perspective, (e) perspective, (f) object-centered. Each diagram shows a top-down view of the projection.
Note how parallel lines on the ground plane and box sides remain parallel in the non-perspective projections.