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Arnold Newman
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How to create 3D using 2D?
• Artists use the various depth cues to convey3D impression:–
Size– Geometrical perspective– Shadow– Color– Sharpness– Patterns–
Overlay (interposition)
However, they are intrinsically ambiguous, can be interpreted in
many ways. We interpret with the most likely possibility.
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A counter example: impossible triangle
developed by Roger Penrose and his father4
Everything is OK for two corners…
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Everything is OK for two corners…
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Everything is OK for two corners…
Each corner presents a different 3D interpretation…
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M.C. Escher
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Impossible trident
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Impossible trident
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Impossible trident
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Necker Cube
http://dogfeathers.com/java/necker.html
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Necker Cube
http://dogfeathers.com/java/necker.html 16
Necker Cube
http://dogfeathers.com/java/necker.html
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Size
• Smaller objects are more distant, andcloser objects are
larger.
• However– Movie producers use this to fool us: take a
close picture of miniature models to get anillusion of the
distance objects or viceversa. “Honey, I shrunk the kids”
– Architects: using smaller window at higherfloors.
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Shape constancyBoth rectangles produce the sameimage on the
retina, but we cantell their orientation…
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Linear perspective
• Parallel receding lines appear as if theyare coming together.
(rail road tracks,light rays from the sun)
• In architecture– Narrower towards the top gives the
impression of a taller structure.• In art
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Linear Persepctive
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Before 1400…
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1st use of linear perspective
Donatello - 142524
Da Vinci - The Last Supper
1498
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25Raphael 1510
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Perspective Illusions
The Ames Room28
The Ames Room
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Shadow
• Shadows are extremely important inproviding us the 3D
impression.
• Light color appears closer to us andhence bigger.
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Variations in Color
• Distant landscapes tend to lose their colorcontrasts. Colors
get duller, less pure.
• A color print seems to have more depth thanthe identical
picture printed in black and white,and shadows can be conveyed
withoutvariation in brightness.
• Distant mountains appear blue due to theblueness of the
intervening air.
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Variations in Sharpness
• Distance objects appear fuzzier, lesssharply focused. Images
are smaller inthe retina. (oil painting)
• Artists convey the feeling of depth by aloss of detail in
distant objects.
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Patterns• An abstract pattern may create the
feeling of depth.
Victor Vasarely
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Victor Vasarely
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Victor Vasarely
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Overlaying
• We perceive one object to be fartherthan another if the second
object blocksour view of the first.
• However, the apparently more distantobject may in fact be
closer but cut insuch a shape that it fully reveals theapparently
closer (but actually farther)object.
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How many depth cues areused?
A Rainy Day - Gustave Caillebotte
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Previous knowledge
• You interpret an image according to theprevious knowledge
stored in your brain.An interpretation against commonexperience is
suppressed.– Inside-out face (Disneyland)– Cube– Stairs
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Hollow Face Illusion
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• The full moon is appears much largerwhen it is near the
horizon than when itis high in the sky.
• Is this an atmospheric effect (refractiongoing through the
atmosphere) orsimply an illusion?
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Debunking the Moon Illusion
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Salvador DaliThe Slave Market with Disappearing Bust of
Voltaire
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49 50Rene Magritte
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