# inertiaTensor

> The inertia tensor of this body, defined as a diagonal matrix in a reference frame positioned at this body's center of mass and rotated by Rigidbody.inertiaTensorRotation.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.3/script-reference/unityengine.md)
* **Assembly:** UnityEngine.PhysicsModule

```csharp
public Vector3 inertiaTensor { get; set; }
```

### Remarks

Inertia tensor is a rotational analog of mass: the larger the inertia component about a particular axis is, the more torque that is required to achieve the same angular acceleration about that axis.

Zero is not a valid inertia tensor component. Therefore, the physics system interprets zeros as infinite values instead. So, for example, a body with (0, 1, 1) inertia tensor is impossible to rotate around X.

Note that the rotational Constraints [RigidbodyConstraints](/engine/6000.3/script-reference/unityengine/rigidbodyconstraints.md) of Rigidbody are actually implemented by setting the inertia tensor components about the locked degrees of freedom to zero.

If you don't set the inertia tensor from a script, it is calculated automatically from all colliders attached to the Rigidbody. To reset the inertia tensor to the automatically computed value, call [Rigidbody.ResetInertiaTensor](/engine/6000.3/script-reference/unityengine/rigidbody/resetinertiatensor.md).

### Examples

```csharp
// Expose tensor of inertia to allow adjustment from
// the inspector.
using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    public Vector3 tensor;
    public Rigidbody rb;
    void Start()
    {
        rb = GetComponent<Rigidbody>();
        rb.inertiaTensor = tensor;
    }
}
```