The Perspective Projection of the shadow are all gushing to some not parallel. The point of this so-called shadow crept into the Center projector station (Center of Projection).
Perspective Projection the light of all the shadows would plunge into a parallel point, a point of light to pierce the shadows is called. The center projector function (Center of Projection).
Perspective Projection. The light of all the shadows will rise to the point where no parallel light spot of shadows rise following called center projection. (Center of Projection).