<!--
{
  "availability" : [
    "iOS: 18.0.0 -",
    "iPadOS: 18.0.0 -",
    "macCatalyst: 18.0.0 -",
    "macOS: 15.0.0 -",
    "tvOS: 26.0.0 -",
    "visionOS: 2.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "RealityKit",
  "identifier" : "/documentation/RealityKit/EntityAction/isAdditive",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "RealityKit"
    ],
    "preciseIdentifier" : "s:17RealityFoundation12EntityActionP10isAdditiveSbvp"
  },
  "title" : "isAdditive"
}
-->

# isAdditive

A Boolean value that determines whether this action
additively blends with the prior stage.

```
var isAdditive: Bool { get }
```

## Discussion

When `true`, the action’s animation output is relative to an absolute base value,
and the animation system blends the result additively with the prior blend stage.

Apply actions additively by configuring them to produce
animation offsets, such as delta values.

The default value is `false`.

---

Copyright &copy; 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)