# Sandbox.PhysicsTraceBuilder.Radius

```csharp
PhysicsTraceBuilder Radius(float radius)
```

Makes this trace a sphere of given radius. Zero (or less) is ignored - the trace keeps its
current shape (a plain ray if none was set).

### Parameters

- `radius` (`float`)

### Returns

`PhysicsTraceBuilder`

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