RealityKit Basics: Create Shapes

Joseph Simpson Updated on

Creating primitive shapes in code.

Overview

In RealityKit, we have two simple ways to create primitive shapes.

  1. Directly in code
  2. In Reality Composer Pro

Oddly, there these two have a different selection of shapes. For example, in code we can generate planes, but in Reality Composer Pro we can’t.

Here are a few example of creating shapes in code. We place these in a volume.

VisionOS simulator screenshots showing five primitive shapes: plane, cone, sphere, cube, and cylinder.

Example Code

struct Example038: View {
    var body: some View {
        RealityView { content, attachments in

            // Create an empty entity we can use to group our shapes
            let group = Entity()
            content.add(group)
            // We can move this group down in the volume and scale it to 50%.
            group.position = [0, -0.25, 0]
            group.scale = [0.5, 0.5, 0.5]

            // Create shapes

            // ModelEntity is a convenient way to create an entity with a model, shapes, and material.
            let sphere = ModelEntity(
                mesh: .generateSphere(radius: 0.1),
                materials: [SimpleMaterial(color: .stepRed, isMetallic: false)])
            // Set the position of the sphere relative to the group
            sphere.setPosition([-0.5, 0, 0], relativeTo: group)
            // Add the sphere as a child to the group
            group.addChild(sphere)

            let box = ModelEntity(
                mesh: .generateBox(size: 0.2),
                materials: [SimpleMaterial(color: .stepGreen, isMetallic: false)])
            box.setPosition([0, -0.1, 0], relativeTo: group)
            group.addChild(box)

            let cylinder = ModelEntity(
                mesh: .generateCylinder(height: 0.2, radius: 0.1),
                materials: [SimpleMaterial(color: .stepBlue, isMetallic: false)])
            cylinder.setPosition([0.5, 0, 0], relativeTo: group)
            group.addChild(cylinder)

            let cone = ModelEntity(
                mesh: .generateCone(height: 0.2, radius: 0.075),
                materials: [SimpleMaterial(color: .stepBlue, isMetallic: false)])
            cone.setPosition([0.4, 0.5, 0], relativeTo: group)
            group.addChild(cone)

            let plane = ModelEntity(
                mesh: .generatePlane(width: 0.2, height: 0.2),
                materials: [SimpleMaterial(color: .stepGreen, isMetallic: false)])
            plane.setPosition([-0.4, 0.5, 0], relativeTo: group)
            group.addChild(plane)

        } update: { content, attachments in
            // More on update later
        } attachments: {
            // More on attachments later
            Attachment(id: "AttachmentContent") {
                Text("")
            }
        }
    }
}

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