# Sandbox.PhysicsGroup.RebuildMass

```csharp
void RebuildMass()
```

Calls [Sandbox.PhysicsBody.RebuildMass](/api/Sandbox.PhysicsBody/RebuildMass) on all bodies of this group.

Declared in [Sandbox.PhysicsGroup](/api/Sandbox.PhysicsGroup).
Assembly: `Sandbox.Engine`.