# Sandbox.PhysicsGroup.Mass

```csharp
float Mass { get; set; }
```

The total mass of all the dynamic[PhysicsBodies](/api/Sandbox.PhysicsBody) in this group.
When setting the total mass, it will be set on each body proportionally to each of their old masses,
i.e. if a body had 25% of previous total mass, it will have 25% of new total mass.

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