Which of the following equation is correct for the new Y co-ordinate if an object undergoes 3D rotation around z axis? a) Ynew = Xold x sinθ – Yold x cosθ b) Ynew = Xold x sinθ + Yold x cosθ c) Ynew = Xold x cosθ – Yold x sinθ d) Ynew = Xold x cosθ + Yold x sinθ
Answer: b Explanation: The correct equation for the new Y co-ordinate if an object undergoes 3D rotation around z axis is – Ynew = Xold x sinθ + Yold x cosθ When the matrix form for 3D rotation around z axis is expanded then we get the following equations – Xnew = Xold x cosθ – Yold x sinθ; Ynew = Xold x sinθ + Yold x cosθ; Znew = Zold.
