Originally proposed as an algorithm for visible surface determination but now used in advanced image synthesis as ray tracing. General idea is to shoot a Ray from eye position through each pixel position. Test this ray for intersection against all objects in the scene. The visible surface is the surface with the closest intersection.
We define a ray in parametric form by an origin Ro and a direction vector Rd. So that R(t)= Ro + t * Rd Note, if Rd is a unit vector then t directly gives the distance along the ray. Ray casting is too computationally intensive to use just for visible surface determination but used for realistic image synthesis.
Visible Surface Determination
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