Moving prefab body parts up and down — stops working when tied to a button click

Question

I'm newbie to Unity and attempting to move a prefab's arm up and down on a button click but having some difficulty.

The arm movement works when called from the Update() method without checking for a button click. Here's a sample of the code:

[SerializeField] Transform rightArm;
int iRotationSpeed = 100;

void Update()
{
    if (Input.GetButtonUp("Button"))  
    {
        // move the arm up
        rightArm.Rotate(Vector3.up * Time.deltaTime * iRotationSpeed, Space.World);   
     
        // now, move the arm back down        
        rightArm.Rotate(Vector3.down * Time.deltaTime * iRotationSpeed, Space.World);
    }
}

Currently using Unity 2021 Personal.

Answer 1

What is your question? You didn't state a specific problem in your post. But what I have found, is that in your first script you rotate something by a tiny amount (Time.DeltaTime is a really small number, say 0.01666... for 60 fps, so you would rotate 100 * 0.016 = 1.6°). It's hard to see these little rotations in the editor, but you rotate the arm right back to it's initial position in the same frame (all code in update is executed once per frame)

if (Input.GetButtonUp("Button") 
{
    rightArm.Rotate(Vector3.up * Time.deltaTime * iRotationSpeed, Space.World); //this rotates by 1.6° upwards
    rightArm.Rotate(Vector3.down * Time.deltaTime * iRotationSpeed, Space.World); //this rotates by 1.6° downwards, in the same frame
}

What you probably meant to do is if button pressed move the arm up, else move the arm down

if (Input.GetButton("Button") 
{
    rightArm.Rotate(Vector3.up * Time.deltaTime * iRotationSpeed, Space.World);
}
else
{
    rightArm.Rotate(Vector3.down * Time.deltaTime * iRotationSpeed, Space.World);
}