# startMassUpdate

> Should the body update its mass properties when this shape is created. Disabling this improves performance when multiple shapes are being added to the same body. The mass of a body can then be explicitly updated by calling PhysicsBody.ApplyMassFromShapes See PhysicsShape.startMassUpdate.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine.LowLevelPhysics2D](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d.md)
* **Assembly:** UnityEngine.Physics2DModule

```csharp
public bool startMassUpdate { readonly get; set; }
```