I'm not sure if this was intentional or not but if you do
my3dObj.rotateY(0.07);
my3dObj.rotateMesh();
in a loop, or repeatedly, you observe what I perceive to be unexpected behavior. What I observed was the calls to rotateY were cumulative, so if i called the rotateY above 10 times, the object would rotate roughly 1 degree after the first call, 2 after the second, 3 degrees after the 3rd and so on.
I expected that rotateMesh() would reset the yRotation value to 0 since it was now permanent, so calling the above two lines of code repeatedly would result in subsequent 1 degree rotations about the Y axis.
I realize that this is not the intended use of rotateMesh, but it may be an issue just the same....