SHADE & SHADOWS
Perspective Views
The casting of shade and shadows in linear perspective is similar
to their construction in para line drawings, except that t he
sloping lines representing the conventional or actual light rays
appear to converge w oblique to the picture plane.
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To determine the vanishing point for inclined
light rays, construct atriangular shadow plane
for a verticals hade line in perspective, having a
hypotenuse establishing the direction o the
f
light rays and a base describing their bearing
direction.
• Because the bearing directions of light rays are
described by horizontal lines, their vanishing
point (VP) m occur somewhere along the
ust
horizon line (HL).
• Establish avanishing trace t hroughVP.
• Extend t hehypotenuse until it intersects the
vanishing trace. This intersectionrepresents
thesourceof the light rays, and is aboveHL
w the light source is infront of the observer
hen
and below HL when behind t h observer.
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• Light sources behind us illuminate t hesurfaces
we see andcast shadows away from us.
• Sources in front of us cast shadowstoward us
and emphasize backlit surfaces in shade.
• Low light angles lengthen shadows. while high
sources shorten them.
RENDERING TONAL VALUES/ 153