JTCgood first issuetype - enhancement
描述
The Billboard documentation states that "The aligned axis is the unit vector that the billboard up vector points towards. The default is the zero vector, which means the billboard is aligned to the screen up vector." This indicates that the aligned axis should be a unit vector.
However, if you give the Billboard a non-normalized "unit" vector, that vector is completely ignored and the default is used instead. I think that either: A) The documentation should clearly state that any non-normalized alignedAxis will be ignored and replaced with the Zero vector. or better yet, B) The alignedAxis should not have to be normalized in the first place. The Cesium code can normalize the axis internally if it needs to.