Lab 008 – Anchor and entity to the head
Create a tracked entity that will update based on head position, then child an entity to it.
In Lab 007 we looked at hand anchors, now let’s take a look at the head anchor. This simple scene will create a sphere with an emoji inside that will be attached to the users head. The anchor itself is at the same coordinates as the users head, so we need to offset the position of our entity so the user can use it. In this case I placed it 1.5 units directly in front of the user.
struct Lab008: View {
// 1. Create an entity that will be anchored to the head
@State var headTrackedEntity: Entity = {
let headAnchor = AnchorEntity(.head)
return headAnchor
}()
var body: some View {
RealityView { content, attachments in
// 2. Create a model to attach to the tracked entity
// Set the Z position to push the model away from the user
let model = ModelEntity(
mesh: .generateSphere(radius: 0.1),
materials: [SimpleMaterial(color: .black, isMetallic: false)])
model.position = SIMD3(x: 0, y: 0, z: -1.5) // position the model in front of the user
model.scale = SIMD3(x: -1, y: 1, z: 1) // flip this inside out
// Bonus: add an attachment to the model
if let attachmentEntity = attachments.entity(for: "AttachmentContent") {
attachmentEntity.scale = .init(repeating: 2.0)
attachmentEntity.components[BillboardComponent.self] = .init()
model.addChild(attachmentEntity)
}
headTrackedEntity.addChild(model)
// 3. Make sure to add the head tracked entity to the scene graph
content.add(headTrackedEntity)
} update: { content, attachments in
//...
} attachments: {
Attachment(id: "AttachmentContent") {
Text("👀")
.font(.extraLargeTitle2)
}
}
}
}Video demo
Video demo of a small character anchored to a users head in visionOS
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