CODEWITHSUNDEEP
scenekitarkitrealitykit
Dgrz
Dgrz

Reputation: 29

ARKit RealityKit WorldMap Persistence

So I have a RealityKit app, in it I add variousEntities. I looked for inspiration for persistence at Apple's SceneKit example with the code, which I implemented only to find out missing Entities upon WorldMap Load

Upvotes: 0

Views: 733

Answers (1)

BCbeau
BCbeau

Reputation: 46

I'm assuming you are able to save and load the worldMap from the ARView's session, but the problem is that this only persists the old styler ARAnchors, and not the cool new Entity objects from the new RealityKit features.

The work around that I did, was to initialize my AnchorEntities, using the constructor that takes an ARAnchor. So, from my hitTest, or RayCast, I take the world transform and save it as an ARAnchor, then use that to initialize an AnchorEntity. I gave this ARAnchor a unique name, to be used later to re-map to an entity upon loading a persisted world map, since this map still only has ARAnchors.

let arAnchor = ARAnchor(name: anchorId, transform: rayCast.worldTransform) // ARAnchor with unique name or ID
let anchorEntity = AnchorEntity(anchor: arAnchor)

That's what it looks like before adding the anchors to the scene for the first time. After you save your world map, close, and reload, I then loop over the loaded or persisted ARAnchors, and associate each anchor with their respective Entities, which maps to the name in the ARAnchor.

let anchorEntity = AnchorEntity(anchor: persistedArAnchor) // use the existing ARAnchor that persisted to construct an Entity
var someModelEntity: Entity = myEntityThatMatchesTheAnchorName // remake the entity that maps to the existing named ARAnchor
anchorEntity.addChild(someModelEntity)
arView.scene.addAnchor(anchorEntity)

It's indirect, but taking advantage of that association between AnchorEntity and ARAnchor was the first solution I could find, given the limitation of only knowing how to persists ARAnchors, and not Entities in the worldMap.

Upvotes: 3

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