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  "title" : "USDPrim.Property.Spec"
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# USDPrim.Property.Spec

A handle to a property definition (attribute or relationship) stored
in a layer.

```
struct Spec
```

## Overview

`USDPrim.Property.Spec` is the untyped base for `USDPrim.Attribute.Spec`
and `USDPrim.Relationship.Spec`. It acts as a handle into data owned
by a [`USDLayer`](/documentation/USDKit/USDLayer) and mutations write through to the layer.

## Topics

### Protocols

[`protocol SymmetryCollection`](/documentation/USDKit/USDPrim/Property/Spec/SymmetryCollection)

Symmetry and naming substitutions used in rigging.

[`protocol ValueCollection`](/documentation/USDKit/USDPrim/Property/Spec/ValueCollection)

Value-related API for property specs that hold typed default values.

### Initializers

[`init()`](/documentation/USDKit/USDPrim/Property/Spec/init())

Creates an empty (invalid) property spec handle.

[`init?(USDLayer.Spec)`](/documentation/USDKit/USDPrim/Property/Spec/init(_:))

Narrows an untyped [`USDLayer.Spec`](/documentation/USDKit/USDLayer/Spec) to a property spec.

### Instance Properties

[`var comment: String?`](/documentation/USDKit/USDPrim/Property/Spec/comment)

The authored user comment, or `nil` if not authored.

[`var customData: Dictionary<String, USDValue>`](/documentation/USDKit/USDPrim/Property/Spec/customData)

The custom data dictionary authored on this property.

[`var documentation: String?`](/documentation/USDKit/USDPrim/Property/Spec/documentation)

The authored documentation, or `nil` if not authored.

[`var isCustom: Bool`](/documentation/USDKit/USDPrim/Property/Spec/isCustom)

Whether this property was authored as `custom`.

[`var name: USDToken`](/documentation/USDKit/USDPrim/Property/Spec/name)

The property’s local name.

[`var owner: USDLayer.Spec?`](/documentation/USDKit/USDPrim/Property/Spec/owner)

The spec that contains this property — typically a prim spec or
variant spec.

[`var permission: USDLayer.Permission`](/documentation/USDKit/USDPrim/Property/Spec/permission)

The property’s permission level (public, restricted, private).

### Instance Methods

[`func clearAssetInfo(String)`](/documentation/USDKit/USDPrim/Property/Spec/clearAssetInfo(_:))

Removes `key` from the asset info dictionary.

[`func clearCustomData(String)`](/documentation/USDKit/USDPrim/Property/Spec/clearCustomData(_:))

Removes `key` from the custom data dictionary.

[`func rename(to: USDToken) throws`](/documentation/USDKit/USDPrim/Property/Spec/rename(to:))

Sets the property’s name.

[`func setAssetInfo(String, to: USDValue)`](/documentation/USDKit/USDPrim/Property/Spec/setAssetInfo(_:to:))

Sets `key` in the asset info dictionary to `value`. Read the
full dictionary via `field("assetInfo")` from FieldCollection.

[`func setCustomData(String, to: USDValue)`](/documentation/USDKit/USDPrim/Property/Spec/setCustomData(_:to:))

Sets `key` in the custom data dictionary to `value`.

### Type Methods

[`static func isValidName(USDToken) -> Bool`](/documentation/USDKit/USDPrim/Property/Spec/isValidName(_:))

Returns a Boolean value that indicates whether `name` is a valid
property name.

## Relationships

### Conforms To

[`ValueCollection`](/documentation/USDKit/USDPrim/Property/Spec/ValueCollection)

[`FieldCollection`](/documentation/USDKit/USDLayer/Spec/FieldCollection)

[`Copyable`](/documentation/Swift/Copyable)

[`Equatable`](/documentation/Swift/Equatable)

[`MetadataCollection`](/documentation/USDKit/USDLayer/Spec/MetadataCollection)

[`SymmetryCollection`](/documentation/USDKit/USDPrim/Property/Spec/SymmetryCollection)

[`Escapable`](/documentation/Swift/Escapable)

---

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