The neighboring parameters must also be animated; for example, if “rx” uses qlinear(), “ry” and “rz” should also use qlinear().
Because the interpolation is done in quaternion spaces, the orientations will blend smoothly with no gimbal lock or unexpected spins. The Euler rotation values may appear to jump suddenly, but that’s simply because different rotation values can represent the same orientation.
Note that the graph editor will display a qlinear() segment as a dashed straight line. This line does not represent the actual intermediate channel values, but it does give an accurate visual feel for the behavior of the interpolation.
This function is one of the special animation functions that use the current playbar time and information in the parameter’s keyframes, such as in and out values, tangents, acceleration, etc., to evaluate themselves. Because the information needed to evaluate these functions comes from the keyframes, these functions take few or no parameters.
Calling this function from outside a parameter’s expression will raise a hou.NotAvailable exception.