Hi am new to the world of 3D graphics as well as to Babylon.js.
You cannot use both a rotation and a rotationQuaternion on a mesh. When a rotationQuaternion is applied to a mesh this overwrites the current and subsequent use of rotation producing the wrong orientation. Should you want to use rotation after a rotationQuaternion has been applied, for example on an imported mesh, then the rotationQuaternion has to be set to null.
To see this effect comment out line 48 in the following playground
Playground Example re-set rotationQuaternion (https://www.babylonjs-playground.com/#1ST43U#77)
In my understanding by commenting out line 48 (which set the rotationQuaternion to null) it is expected that the two boxes will not be aligned anymore. But the example doesn’t seem to do that.
Something seems amiss with my understanding / the example ?