How to animate a 3D spherical rotation with GUIDE?

Hi,

I am currently developing a code that allows the rotation of a 3D sphere using MATLAB's GUIDE.

The method used is using quaternions, and it works fine actually. The issue is the reverse rotation, where a sphere rotates one direction but when pressing a button in the UI, it reverses direction. From many online sources, it says that the inverse rotation of a quaternion is equal to negating the vector terms and dividing both scalar and vector terms by the magnitude. Implementing this into the MATLAB code, the sphere does not smoothly transition and rotate.

Does anyone know if this is the correct methodology?

Thanks in advance, Tony