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# setComponent(_:for:)

Associates a component with the object for the specified protocol.

```
func setComponent(_ component: any MDLComponent, for protocol: Protocol)
```

## Parameters

`component`

The component to associate with the object. The component class must adopt the protocol specified in the `protocol` parameter.

`protocol`

The protocol whose functionality the component provides.

## Discussion

Components are the basis for customizable file format and object graph support in Model I/O. By default, the [`MDLObject`](/documentation/ModelIO/MDLObject) uses the [`MDLObjectContainerComponent`](/documentation/ModelIO/MDLObjectContainerComponent) and [`MDLTransformComponent`](/documentation/ModelIO/MDLTransformComponent) protocols to model object hierarchies and spatial transforms: When you load an object graph from a [`MDLAsset`](/documentation/ModelIO/MDLAsset) instance, Model I/O creates container and transforms components to represent the object hierarchy and spatial relationships described in the asset file. However, you can also create custom components. For example, a custom component protocol could add support for an asset format that encodes gameplay-related information such as scripting triggers, or a custom class for the [`MDLObjectContainerComponent`](/documentation/ModelIO/MDLObjectContainerComponent) could implement other ways to store or traverse object hierarchies.

---

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