Geometric transformation of an object in three-dimensional space characterized by one or more fixed points called centres of projection and a projection plane that does not contain these points.
The central projections are also called conic projections because all of the vanishing lines relative to a fixed point pass through the apex of a cone situated at this point.
- The line that contains the image of a fixed point is called the horizon. If we project based on more than one fixed point, we obtain as many horizons as fixed points. We can project using one, two, or three fixed points, depending on the desired effect. Here is a central projection with one fixed point:
- A central projection provides a plane image of a three-dimensional object with a visual effect that gives the impression of depth that is more or less realistic, depending on the parameters chosen.
- Central projections preserve the parallelism of lines that belong to planes perpendicular to the projection plane.
- The images obtained on the projection plane form representations in perspective that convey the effect of three-dimensional depth with more or less realism. We call these images perspectives with one, two, or three vanishing points, depending on the number of fixed points used to obtain the projected image.