Distinguish between parallel and perspective projection
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Parallel Projection
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Perspective projection
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Coordinate position are transformed to view plane along parallel lines. The vector defining the direction of lines is called projection vector.
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Coordinate position are transformed
to view plane along lines that converge to a point called projection reference point (PRP).
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Object distance from the view plane is not significant.
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Object's distance from the PRP and view plane is important. It plays a role in determining size of the image.
Farther the object, smaller is the image.
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Parallel lines remain parallel.
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Parallel lines may not remain parallel.
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Ratios are preserved in general.
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Ratio are not preserved in general.
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Useful in civil, architectural design, machine design, sectional view design, etc.
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Useful in virtual reality, gaming and other such applications.
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Less realistic.
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More realistic.
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