The Quaternion Structure
Different authors use different letters for the four real numbers of the quaternion. I earlier represented the quaternion as:
Here's one variation:
The Quaternion structure defined in the System.Windows.Media.Media3D namespace defines properties named W, X, Y, and Z for the four components, so to avoid confusion I will tend to use those same letters in lower case:
Although this is the standard order for notating these components, ...