Question

General pivot point rotation can be expressed as _____________________

(a) T(zr,yr).R(θ).T(-zr,-yr) = R(xr,yr,θ)

(b) T(xr,yr).R(θ).T(-xr,-yr) = R(xr,yr,θ)

(c) T(xr,yr).R(θ).T(-xr,-yr) = R(zr,yr,θ)

(d) T(xr,yr).R(θ).T(-xr,-yr) = R(xr,yr,Q)

I have been asked this question in a job interview.

I would like to ask this question from Composite 2D Transformations in chapter 2D Transformation and Viewing of Computer Graphics

Answer 1

The correct answer is (b) T(xr,yr).R(θ).T(-xr,-yr) = R(xr,yr,θ)

Explanation: Since the first two parameters are in 2D, hence only ‘x’ and ‘y’ can be variable along with ‘θ’. In other options, there is one more parameter ‘z’.