9. Which of the following equation is correct for the new Z co-ordinate if an object undergoes 3D rotation around x axis? A. Znew = Yold x sinθ – Zold x cosθ B. Znew = Yold x sinθ + Zold x cosθ C. Znew = Yold x cosθ – Zold x sinθ D. Znew = Yold x cosθ + Zold x sinθ
Ans : B Explanation: The correct equation for the new Z co-ordinate if an object undergoes 3D rotation around x axis is – Znew = Yold x sinθ + Zold x cosθ. When the matrix form for 3D rotation around x axis is expanded then we get the following equations – Xnew = Xold; Ynew = Yold x cosθ – Zold x sinθ; Znew = Yold x sinθ + Zold x cosθ.
