# addCustomParameter(withName:parameterID:defaultValue:parameterFlags:) Creates a custom parameter and adds it to the plug-in’s parameter list. ``` func addCustomParameter(withName name: String, parameterID: UInt32, defaultValue: any NSCopying & NSSecureCoding & NSObjectProtocol, parameterFlags flags: FxParameterFlags) -> Bool ``` ## Parameters `name` Name of the parameter in the user interface. `parameterID` Unique identifier for a parameter. Used to retrieve, set, or validate the parameter. `defaultValue` Initial entry for the parameter. `flags` Flags that encode various state values for the parameter. ## Return Value Returns `YES` if the application successfully creates a custom parameter; `NO` otherwise. ## Discussion The `defaultValue` argument is an instance, created by the plug-in, of the custom parameter’s class, which must conform to the protocol. `NSCoding` is used for serializing and unserializing the custom parameter’s value object for saving and loading. > Note: Your implementation of (`-encodeWithCoder:` and `-initWithCoder:`) must use keyed coding. If you have a custom parameter, you must implement the `FxCustomParameterInterpolation_v2` protocol for your custom class and implement the ``doc://com.apple.professionalvideoapplications/documentation/professional_video_applications/FxTileableEffect/classes(forCustomParameterID:)`` method in your plug-in. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)