---
title: "add(_:position:)"
framework: usdkit
role: symbol
role_heading: Instance Method
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, macOS 27.0+, tvOS 27.0+, visionOS 27.0+]
path: "usdkit/usdprim/referencecollection/add(_:position:)"
---

# add(_:position:)

Adds an existing reference arc to the prim.

## Declaration

```swift
func add(_ reference: USDPrim.Reference, position: USDPrim.ListPosition = .backOfPrependList) throws
```

## Parameters

- `reference`: The reference to add.
- `position`: Where to insert the reference in the prim’s reference list.

## Discussion

Discussion note: An error if the reference cannot be added.