# Projections:Â **Perspective Projection**

Perspective Projection is the important topic of the Computer Graphics. Moreover, It is the Important subject of the Computer Science & Technological field.

Once world-coordinate descriptions of the objects in a scene converted to viewing coordinates, we can project the three-dimensional objects onto the two-dimensional view plane.

The process of converting three-dimensional coordinates into the two-dimensional scene known as **projection**.

Moreover, There are two projection methods namely.

- Parallel Projection.
- Perspective Projection.

Also, Let us discuss Perspective Projections.

**Perspective Projections**

- Fig. Perspective projection.
- In perspective projection object positions transformed to the view plane along lines that converge to a point called the
**projection reference point**(or**center of projection**or**vanishing point**).

- Fig. Perspective projection.
- Also, Suppose we set the projection reference point at position z
_{prp}along the z_{v}axis, and we place the view plane at z_{vp}as shown in Figure above. We can write equations describing coordinate positions along this perspective projection line in parametric form as

đ^{â˛ }= đ â đđ

đ^{â˛ }= đ â đđ

đ^{â˛ }= đ â (đ â đ_{đđđ})đ

- Here parameter u takes the value from 0 to 1, which is depends on the position of an object, view plane, and projection reference point.
- Moreover, For obtaining a value of u we will putzâ=z
_{vp}and solve an equation of zâ.

- Also, The vanishing point for any set of lines that parallel to one of the principal axes of an object is referred to as a principal vanishing point
- We control the number of principal vanishing points (one, two, or three) with the orientation of the projection plane. Also, And perspective projections are accordingly classified as one-point, two-point, or the three-point projections.
- Moreover, The number of principal vanishing points in a projection is determined by the number of principal axes intersecting the view plane.

**Related Terms**

Computer Graphics, Viewing Pipelines, Projections, General 3D Rotations

## Leave a Reply