[ODE] Angular velocity

[Yefei He]

Hi, 

    Is there any reason why angular velocities seem to be the opposite of 
rotation angles? To state it less confusingly, I have an object starting 
at pos(0,0,0) and rotx =0, roty = 0, rotz =0. If I set the angular 
velocity around z to be a positive value, then as I look down at the 
object from above, it is actually rotating clockwise, not counterclockwise 
as I expect. But if I give the object a positive rotz value, it rotates 
counterclockwise for the given amount. Is there any convention in dynamics 
that leads to this? 

    Thanks, 

    Yefei