# 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 PhysicsShapeDefinition.startMassUpdate.

## Definition

* **Type:** Property
* **Namespace:** [Unity.U2D.Physics](/engine/7000.0/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

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