Revision history [back]

It would be much easier for you to use the start/end point method of specifying an arrow marker than the position orientation method.

You can normalize the velocity vector (divide each element by it's length) and add it to the current position to produce the end point. This way the arrow will always have a length of 1. You'll have to be careful and catch the case where it's velocity is zero since the end point will be a NAN. This arrow will always point in the velocity direction weather it's positive or negative.

Hope this helps.