Rigidbody.angularVelocity

Description

The angular velocity vector of the rigidbody measured in radians per second.

In most cases you should not modify it directly, as this can result in unrealistic behaviour. Note that if the Rigidbody has rotational constraints set, the corresponding angular velocity components are set to zero in the mass space (ie relative to the inertia tensor rotation) at the time of the call. Additionally, setting the angular velocity of a kinematic rigidbody is not allowed and will have no effect.

// Change the material depending on the speed of rotation
using UnityEngine;

public class ExampleClass : MonoBehaviour
{
    public Material fastWheelMaterial;
    public Material slowWheelMaterial;
    public Rigidbody rb;
    public MeshRenderer rend;

    void Start()
    {
        rb = GetComponent<Rigidbody>();
        rend = GetComponent<MeshRenderer>();
    }

    void Update()
    {
        if (rb.angularVelocity.magnitude < 5)
            rend.sharedMaterial = slowWheelMaterial;
        else
            rend.sharedMaterial = fastWheelMaterial;
    }
}