GraphExport (ML export)

OCCTSwiftIO adds a consumption-side ML repacking layer as an extension on OCCTSwift.TopologyGraph: flat vertex positions, per-edge boundary/manifold flags, and COO-format sparse adjacency for face / edge / vertex incidence. (Hoisted from OCCTSwift per OCCTSwiftIO#1 — pure batch / headless, fitting this package’s charter.)

Topics

• TopologyGraph.GraphExport · TopologyGraph.exportForML() · TopologyGraph.exportJSON()

TopologyGraph.GraphExport

Graph data in ML-friendly form: flat arrays plus COO sparse adjacency.

public struct GraphExport: Sendable {
    /// Nx3 vertex positions (each inner array is [x, y, z]).
    public let vertexPositions: [[Double]]
    /// Per-edge boundary flag.
    public let edgeBoundaryFlags: [Bool]
    /// Per-edge manifold flag.
    public let edgeManifoldFlags: [Bool]
    /// Per-face list of adjacent face indices.
    public let faceAdjacentFaces: [[Int]]
    /// Face-to-edge incidence in COO format.
    public let faceToEdge: (sources: [Int], targets: [Int])
    /// Edge-to-vertex incidence in COO format.
    public let edgeToVertex: (sources: [Int], targets: [Int])
    /// Face-to-face adjacency in COO format.
    public let faceToFace: (sources: [Int], targets: [Int])
}

Each COO pair is two parallel arrays: sources[i] → targets[i] is one edge of the incidence graph.

TopologyGraph.exportForML()

Builds a GraphExport from the graph (vertex positions, per-edge flags, face adjacency, and the three COO incidence relations).

public func exportForML() -> GraphExport

• Returns: a GraphExport value.
• Example:

  let export = shape.topologyGraph().exportForML()
  let (src, tgt) = export.faceToFace
  print(export.vertexPositions.count, "vertices,", src.count, "face-face edges")
  

TopologyGraph.exportJSON()

Serializes the export as JSON for ML pipelines. The tuple-typed COO pairs are flattened into parallel *Sources / *Targets arrays in the JSON.

public func exportJSON() -> Data?

• Returns: encoded JSON Data, or nil if encoding fails.
• Example:

  if let data = shape.topologyGraph().exportJSON() {
      try data.write(to: graphURL)
  }