# UGC-NET | UGC NET CS 2016 Aug – III | Question 17

In perspective projection (from 3D to 2D), objects behind the centre of projection are projected upside down and backward onto the view-plane. This is known as _____.**(A)** Topological distortion**(B)** Vanishing point**(C)** View confusion**(D)** Perspective foreshortening**Answer:** **(C)****Explanation:**

- In perspective projection (from 3D to 2D), objects behind the centre of projection are projected upside down and backward onto the view-plane. This is known as view confusion.
- Vanishing point: Where all parallel points appear to meet is called vanishing point.
- Perspective foreshortening: As we move from centre of projection size of object varies inversely with distance, this is known as perspective foreshortening.
- Topological Distortion: A line segment joining a point lying in front of the viewer to a point in back of the viewer is projected to a broken line of infinite extent.This is known as topological distortion.

So, option (C) is correct.