Measurements

These five types provide annotation data structures for distance, angle, and radius measurements displayed as viewport overlays. Measurements are value types suitable for encoding/decoding; clients accumulate them into a ViewportController and render them via the MeasurementOverlay SwiftUI view.

Topics

• ViewportMeasurement · MeasurementMode · DistanceMeasurement · AngleMeasurement · RadiusMeasurement

ViewportMeasurement

ViewportMeasurement is an enum that wraps the three concrete measurement types. It conforms to Identifiable and Sendable, enabling safe integration with SwiftUI state and Combine pipelines.

Cases

case distance(DistanceMeasurement)

A point-to-point distance measurement.

public enum ViewportMeasurement: Identifiable, Sendable {
    case distance(DistanceMeasurement)
}

case angle(AngleMeasurement)

An angle measurement between three points.

public enum ViewportMeasurement: Identifiable, Sendable {
    case angle(AngleMeasurement)
}

case radius(RadiusMeasurement)

A radius or diameter measurement.

public enum ViewportMeasurement: Identifiable, Sendable {
    case radius(RadiusMeasurement)
}

id

Unique identifier derived from the wrapped measurement.

public var id: String { get }

Extracts and returns the id field from the wrapped value (e.g., DistanceMeasurement.id). Enables use in SwiftUI lists and ForEach loops.

• Returns: The String ID of the wrapped measurement.
• Example:

  let meas: ViewportMeasurement = .distance(DistanceMeasurement(start: .zero, end: SIMD3(10, 0, 0)))
  print(meas.id)  // UUID-based identifier
  

DistanceMeasurement

DistanceMeasurement records the start and end points of a point-to-point distance measurement. It conforms to Identifiable and Sendable.

init(id:start:end:label:)

Creates a distance measurement between two world-space points.

public init(id: String = UUID().uuidString, start: SIMD3<Float>, end: SIMD3<Float>, label: String? = nil)

• Parameters:
  • id — unique identifier (default: UUID string).
  • start — first point in world coordinates.
  • end — second point in world coordinates.
  • label — optional text override; if nil, the computed distance is used.
• Example:

  let m = DistanceMeasurement(start: SIMD3(0, 0, 0), end: SIMD3(10, 0, 0))
  print(m.distance)  // 10.0
  

Properties

id

Unique identifier for this measurement.

public let id: String

• Example:

  let m = DistanceMeasurement(id: "dist-1", start: .zero, end: SIMD3(5, 0, 0))
  

start

Start point in world coordinates.

public var start: SIMD3<Float>

• Example:

  let m = DistanceMeasurement(start: SIMD3(1, 2, 3), end: SIMD3(4, 5, 6))
  

end

End point in world coordinates.

public var end: SIMD3<Float>

• Example:

  var m = DistanceMeasurement(start: .zero, end: SIMD3(10, 0, 0))
  m.end = SIMD3(5, 0, 0)
  

label

Optional label override for custom text display.

public var label: String?

If nil, the overlay displays the computed distance value formatted as a string.

• Example:

  var m = DistanceMeasurement(start: .zero, end: SIMD3(50, 0, 0))
  m.label = "Gap: 50 mm"
  

distance

The computed Euclidean distance between start and end.

public var distance: Float { get }

Computed as simd_length(end - start). Always non-negative.

• Returns: Distance in world units.
• Example:

  let m = DistanceMeasurement(start: .zero, end: SIMD3(3, 4, 0))
  print(m.distance)  // 5.0
  

midpoint

The midpoint for label placement.

public var midpoint: SIMD3<Float> { get }

Computed as (start + end) * 0.5. Useful for positioning the measurement label in the viewport.

• Returns: World-space midpoint.
• Example:

  let m = DistanceMeasurement(start: SIMD3(0, 0, 0), end: SIMD3(10, 0, 0))
  print(m.midpoint)  // (5, 0, 0)
  

AngleMeasurement

AngleMeasurement records three points that form an angle, with the vertex at the middle point. It conforms to Identifiable and Sendable.

init(id:pointA:vertex:pointB:label:)

Creates an angle measurement.

public init(id: String = UUID().uuidString, pointA: SIMD3<Float>, vertex: SIMD3<Float>, pointB: SIMD3<Float>, label: String? = nil)

• Parameters:
  • id — unique identifier (default: UUID string).
  • pointA — first arm endpoint.
  • vertex — the angle vertex (corner point).
  • pointB — second arm endpoint.
  • label — optional text override; if nil, the computed degrees are used.
• Example:

  let m = AngleMeasurement(
      pointA: SIMD3(1, 0, 0),
      vertex: SIMD3(0, 0, 0),
      pointB: SIMD3(0, 1, 0)
  )
  print(m.degrees)  // 90.0
  

Properties

id

Unique identifier for this measurement.

public let id: String

pointA

First arm endpoint.

public var pointA: SIMD3<Float>

vertex

Vertex point (where the angle is measured).

public var vertex: SIMD3<Float>

pointB

Second arm endpoint.

public var pointB: SIMD3<Float>

label

Optional label override for custom text display.

public var label: String?

If nil, the overlay displays the computed degrees value.

• Example:

  var m = AngleMeasurement(pointA: SIMD3(1, 0, 0), vertex: .zero, pointB: SIMD3(0, 1, 0))
  m.label = "45°"
  

degrees

The computed angle in degrees.

public var degrees: Float { get }

Computed using ProjectionUtility.angle(_:vertex:_), which calculates the angle formed by rays from the vertex to the two endpoints. Returns a value in the range [0, 180].

• Returns: Angle in degrees.
• Example:

  let m = AngleMeasurement(
      pointA: SIMD3(1, 0, 0),
      vertex: .zero,
      pointB: SIMD3(0, 1, 0)
  )
  print(m.degrees)  // ~90.0
  

RadiusMeasurement

RadiusMeasurement records the center and an edge point of a circular arc or circle, optionally displaying as diameter. It conforms to Identifiable and Sendable.

init(id:center:edgePoint:showDiameter:label:)

Creates a radius or diameter measurement.

public init(id: String = UUID().uuidString, center: SIMD3<Float>, edgePoint: SIMD3<Float>, showDiameter: Bool = false, label: String? = nil)

• Parameters:
  • id — unique identifier (default: UUID string).
  • center — center point of the circle/arc.
  • edgePoint — a point on the circle/arc edge.
  • showDiameter — if true, display diameter (2× radius); if false, display radius (default: false).
  • label — optional text override; if nil, the computed radius or diameter is used.
• Example:

  let m = RadiusMeasurement(center: .zero, edgePoint: SIMD3(5, 0, 0))
  print(m.radius)     // 5.0
  print(m.diameter)   // 10.0
  

Properties

id

Unique identifier for this measurement.

public let id: String

center

Center point of the circle/arc.

public var center: SIMD3<Float>

edgePoint

A point on the circle/arc edge.

public var edgePoint: SIMD3<Float>

showDiameter

Whether to display as diameter (true) or radius (false).

public var showDiameter: Bool

• Example:

  var m = RadiusMeasurement(center: .zero, edgePoint: SIMD3(10, 0, 0))
  m.showDiameter = true  // display as "Diameter: 20"
  

label

Optional label override for custom text display.

public var label: String?

If nil, the overlay displays either the computed radius or diameter (controlled by showDiameter).

• Example:

  var m = RadiusMeasurement(center: .zero, edgePoint: SIMD3(25, 0, 0))
  m.label = "R25"
  

radius

The computed radius (distance from center to edgePoint).

public var radius: Float { get }

Computed as simd_length(edgePoint - center).

• Returns: Radius in world units.
• Example:

  let m = RadiusMeasurement(center: .zero, edgePoint: SIMD3(3, 4, 0))
  print(m.radius)  // 5.0
  

diameter

The computed diameter (2× radius).

public var diameter: Float { get }

Computed as radius * 2.0.

• Returns: Diameter in world units.
• Example:

  let m = RadiusMeasurement(center: .zero, edgePoint: SIMD3(5, 0, 0))
  print(m.diameter)  // 10.0
  

MeasurementMode

MeasurementMode is an enum that controls which measurement tool is active. It conforms to Sendable and Equatable, enabling state management in ViewportController.

Cases

case none

No measurement tool active; measurements cannot be added.

public enum MeasurementMode: Sendable, Equatable {
    case none
}

case distance

Measuring point-to-point distance (accumulates 2 points).

public enum MeasurementMode: Sendable, Equatable {
    case distance
}

case angle

Measuring angle between three points (accumulates 3 points: pointA, vertex, pointB).

public enum MeasurementMode: Sendable, Equatable {
    case angle
}

case radius

Measuring radius or diameter (accumulates 2 points: center, edgePoint).

public enum MeasurementMode: Sendable, Equatable {
    case radius
}

Usage Example

@MainActor
class ViewportController: ObservableObject {
    @Published var measurementMode: MeasurementMode = .none
    
    func addMeasurementPoint(_ point: SIMD3<Float>) {
        switch measurementMode {
        case .none:
            break
        case .distance:
            // accumulate point; create DistanceMeasurement when 2 points collected
            break
        case .angle:
            // accumulate point; create AngleMeasurement when 3 points collected
            break
        case .radius:
            // accumulate point; create RadiusMeasurement when 2 points collected
            break
        }
    }
}