Hi, I need the rotation speed (x,y,z-vector) of an object. I know how to calculate speed in general:

The problem is that the pan, roll and tilt takes values that are going up and down and up and down (0=>360=>0 or 0=>90=>0=>-90 or 0=>180=>-180=>0). It's not possible to calculate the right speed then. Any idea ?

You only need the difference of both values.

abs() gives you always the positive value, independently of the sign of your value.

"speedX = abs(my.pan - copy); "

Additionally you can also use ang() to shift the angles into an -180 to 180 range.
See: http://www.conitec.net/beta/avar-ang.htm

Ok, but I need the exact vector. For example:
x: 0,5 y: -0,3 z: 0,1
A negative rotation is needed to know if the object is turning the other way.

"tilt" is a bit weird, it goes:
0 up to 179.999 and then it switchs to -179.999 and then up to 0 again. So the difference is wrong when one variable is in the positive area and one in the negative. For example:
copy = 179
my.pan = -160
speedX = abs(my.pan - copy);
SpeedX is 339 then.

It's all a bit more complex as it seems

abs() gives you the amount of the speed.
sign() gives you the sign.

Maybe, you can explain what you want to achieve in the end.
As long as you speak of speed, I understand that you want to know an amount, because minus or plus is about the 'direction' of a speed.

To get the differences of whole vector:

vec_set(vector_of_copied_speed, my.pan);
wait(1);
vec_diff(vector_of_speed, vector_of_copied_speed, my.pan);

Oh sorry, I see...I want the speed and the direction in one ^^
x: 0,5 y: -0,3 z: 0,1
0,5 rotation speed in x-direction, -0.3 rotation speed in y-direction and 0.1 rotation speed in y-direction.
Hmmm...is that possible ?

Its already there using Pappenheimer's vec_diff. Lets say the result of the formula is like so.
vector_of_speed.x = -5
vector_of_speed.y = 10
vector_of_speed.z = 15
That means the object has a
X-SPEED = rotating at 5 degrees per frame.(because abs(X) = 5)
X-DIRECTION = rotating anti-clockwise (because X is a negative number)
Y-SPEED = tilting at 10 degrees per frame.(because abs(Y) = 10)
Y-DIRECTION = tilting clockwise(upwards?) (because Y is a positive number)
Z-SPEED = tilting at 15 degrees per frame.(because abs(Z) = 15)
Z-DIRECTION = rolling clockwise (because Z is a positive number)

vec_set(vector_of_copied_speed, my.pan) creates really weird values, not very usefull ^^

With "speed = abs(my.pan - copy)" I can't get the direction, but its the (only ?) way to calculate the speed. And tilt and roll are again different things, with values that are not only going down and up but that are jumping around.

It's possible to calculate the speed and direction without pan, tilt and roll ? Cause these properties are behaving very unhandy.

Not really, because pan, tilt, and roll ARE the rotation you are trying to measure.
So how can we measure anything if we ignore them?

Try taking a step back, and try to get the problem sorted out for JUST pan.
And extend the coding to tilt and roll only after PAN is working.

Also, try re-phrasing your question again. I think all us "experts" may have mis-understood
what it is that you actually want.
Do you want to find out how fast it is turning?
OR
Do you want to know its speed IN-SPACE, as in a sum of SpeedX & SpeedY & SpeedZ = TrueSpeed?
(that is its speed as a true distance, as-the-crow-flies)

Ok, taking a step back is a good idea At the end I want a vector that does exactly this what you wrote:

X-SPEED = rotating at 5 degrees per frame.(because abs(X) = 5)
X-DIRECTION = rotating anti-clockwise (because X is a negative number)
Y-SPEED = tilting at 10 degrees per frame.(because abs(Y) = 10)
Y-DIRECTION = tilting clockwise(upwards?) (because Y is a positive number)
Z-SPEED = tilting at 15 degrees per frame.(because abs(Z) = 15)
Z-DIRECTION = rolling clockwise (because Z is a positive number)

(The speed in-space is already done ^^)

Ok, we can get the speed of the rotation (of pan) and we need abs() for that. But the direction of the speed cannot be calculated with this method, because the differents between the pan's can be negative or positive, independently from the direction.