How to ask Blender to return an angle of a tangent in a driver? My vehicle is driving along it’s locale Y-axis. When it encounters a hill the empty on the front lifts up and creates an angle with the empty at the rear.  How can I ask Blender to return the angle in a driver math expression for the vehicle to rotate on its X-axis. See image.
The Y is known as a fixed construction value of the verhicle (6 meter)
Z = ( z-location Empty Front) – (z-location Empty Rear)
To calculate the tangent in the driver :
Var_1 = z-location Empty Front
Var_2 = z-location Empty Rear
Expression for tangent : (Var_1 – Var_2) / 6
So I have the tangent, how do I get the angle ?
I tryed this : arctan((var_1-var_2)/6), but Blender sais ERROR : invalid Python expression
The python function is atan() not arctan(), and generally its better to use atan2(y, x) instead of atan(y/x) because the former won't generate division by zero.
Also note you have the hypotense so you want asin(var_1-var_2)/6) to get $\alpha$ since you haven't actually found Y. See https://docs.blender.org/manual/en/latest/animation/drivers/drivers_panel.html#simple-expressions