# Sandbox.VertexBuffer.AddRawIndex

```csharp
void AddRawIndex(int i)
```

Add an index. This is NOT relative to the top of the vertex buffer.

### Parameters

- `i` (`int`)

### Exceptions

- `System.InvalidOperationException`: Thrown when [Sandbox.VertexBuffer.Indexed](/api/Sandbox.VertexBuffer/Indexed) is false.

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