---
title: "init(_:)"
framework: usdkit
role: symbol
role_heading: Initializer
path: "usdkit/usdprim/attribute/spec/init(_:)"
---

# init(_:)

Narrows an untyped USDLayer.Spec to an attribute spec.

## Declaration

```swift
init?(_ spec: USDLayer.Spec)
```

## Parameters

- `spec`: The spec to narrow.

## Return Value

Return Value An attribute spec, or nil if spec is not an attribute spec.