Calculate the vertical speed of a transform in any direction

Hi.
I have a simple game object, and I want to calculate the speed of Z-axis of the game object when it moves around the scene.

I mean, calculation of the move forwarding velocity of the game object, in any direction.
For more explanation, I uploaded an image:



To doing this, I tried the below code, but since the game object rotates, (for example 90 degrees), the velocity of Z-direction comes to 0.

Code (CSharp):

1.  
2. float V = 0;
3. void Update()
4.     {
5.         V = V - transform.position.z;
6.         print(V);
7.         V = transform.position.z;
8. }
9.  

How can I solve this problem?

 

I believe you want to use this method on your complete Velocity vector, then consider the .z field of the resulting vector:

https://docs.unity3d.com/ScriptReference/Transform.InverseTransformVector.html

 

Yes, Thanks.