<!--
{
  "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/Entity/ConfigurationCatalog/init(configurationSets:combinations:)",
  "metadataVersion" : "0.1.0",
  "role" : "Initializer",
  "symbol" : {
    "kind" : "Initializer",
    "modules" : [
      "RealityKit"
    ],
    "preciseIdentifier" : "s:17RealityFoundation6EntityC20ConfigurationCatalogV17configurationSets12combinationsAESayAE0D3SetVG_SayAE0D11CombinationVGtKcfc::OverloadGroup"
  },
  "title" : "init(configurationSets:combinations:)"
}
-->

# init(configurationSets:combinations:)

Creates a configuration catalog from in-memory entities and an array of configuration sets.

```
init(configurationSets: [Entity.ConfigurationCatalog.ConfigurationSet], combinations: [Entity.ConfigurationCatalog.ConfigurationCombination]) throws
```

## Parameters

`configurationSets`

The configuration choices that the configuration catalog presents.
Each configuration set needs to have a unique ID from all others.
The configuration catalog stores the array as the `configurationSets` dictionary
property and doesn’t preserve its order.

`combinations`

The combinations of in-memory entities and the configurations that can
address them.
The keys you use in
[`configurationSpecifications`](/documentation/RealityKit/Entity/ConfigurationCatalog/ConfigurationCombination/configurationSpecifications) need to match
IDs of configuration sets from the `configurationSets` argument.
The values you use in
[`configurationSpecifications`](/documentation/RealityKit/Entity/ConfigurationCatalog/ConfigurationCombination/configurationSpecifications) need to match
IDs of configurations from the `configurationSets` argument.
There needs to be one [`Entity.ConfigurationCatalog.ConfigurationCombination`](/documentation/RealityKit/Entity/ConfigurationCatalog/ConfigurationCombination) for each possible combination
of configurations.

## Return Value

A configuration catalog that maintains the provided entities in memory.

---

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)