04/09/2002
15-462 Graphics I
6
Solid Angle
•2D angle subtended by object O from
point x:
–Length
of projection onto unit circle at x
–Measured
in radians (0 to 2p)
•3D solid angle subtended by O from
point x:
–Area
of of projection onto unit sphere at x
–Measured
in steradians (0 to 4p)
J. Stewart