Types of Perspective Projection

TYPES OF PERSPECTIVE PROJECTION

Perspective projections are mainly classified into three categories based on the relative position of the object with respect to the picture plane as below:

1. One point perspective (or Parallel perspective)

2. Two point perspective (or Angular perspective)

3. Three point perspective (or Oblique perspective)

1. One point perspective (or Parallel perspective)

If the principal face of the object viewed is parallel to the picture plane, the perspective view formed is called "Parallel perspective" or One point perspective.

In one point perspective all the horizontal lines receding the object (ie. AE, DF, CG in Fig. 18.3) converge to a single point called vanishing point.

But the vertical and horizontal lines on the principal face and parallel to the picture plane (ie. AD, DC, CB, AB etc.) do not converge.

This type of perspective view is generally used for roads, rail road, or such objects which are viewed directly from the front. One point perspective is also used to show the interior details of rooms, interior features of various components etc.

2. Two point perspective (or Angular perspective) 

If the two principal faces of the object viewed are inclined to the picture plane, the perspective view formed is called "Angular perspective" or Two point perspective.

In two point perspective, all the horizontal lines (AE, BF, CG, AD, BC, FG in Fig.18.4) converge to two different points called vanishing point left (VPL) and Vanishing Point Right (VPR). But the vertical lines (AB, DC etc.,) remain vertical.

This type of perspective view is generally used to represent the pictorial views of long side and wide objects like buildings, structures etc.

3. Three point perspective (or Oblique perspective)

If all the three mutually perpendicular faces of the object viewed are inclined to the picture plane, the perspective view formed is called "Obligue perspective" or Three point perspective. 

In three point perspective, all the horizontal lines (FG, BC, AD, AE, CG etc.) converge to two different points called Vanishing Point Left (VPL) and Vanishing Point Right (VPR) and all the vertical lines (DC, AB, EF in Fig. 18.5.) converge to a third vanishing point located either above (or) below the horizon line.

Three point perspective is generally used to draw pictorial views of huge and tall objects like tall buildings, towers, structures etc.