The ScriptManifest format

A ScriptManifest is the JSON document a script harness writes to describe a scene: a list of bodies, each pointing at a sibling BREP file, with optional color and PBR material hints. It is a pure Codable value type — decoding it does not require linking OCCT.

Loading a manifest + its BREP bodies

ShapeLoader.loadFromManifest(at:) decodes the manifest, then loads each BodyDescriptor.file relative to the manifest’s own directory (skipping any whose file is missing). Note this entry point is synchronous throws (not async):

import OCCTSwift
import OCCTSwiftIO

let result = try ShapeLoader.loadFromManifest(at: manifestURL)   // .../manifest.json
for (shape, color) in result.shapesWithColors { /* … */ }

// The decoded manifest is preserved on the result:
if let manifest = result.manifest {
    print(manifest.description ?? "", manifest.bodies.count, "bodies")
}

The shape of the document

public struct ScriptManifest: Codable, Sendable {
    public let version: Int
    public let timestamp: Date
    public let description: String?
    public let bodies: [BodyDescriptor]
    public let metadata: ManifestMetadata?
}

Each body references a BREP file and carries optional appearance hints:

public struct BodyDescriptor: Codable, Sendable {
    public let id: String?
    public let file: String       // resolved relative to the manifest's directory
    public let format: String
    public let name: String?
    public let roughness: Float?
    public let metallic: Float?
    public var color: SIMD4<Float>?   // decoded from a [r, g, b, a] JSON array
}

color is stored in JSON as a four-element [r, g, b, a] array under the key "color" and surfaced as a SIMD4<Float>? (nil when absent or shorter than four elements).

Decoding manifest JSON yourself

ScriptManifest is plain Codable; the timestamp is ISO-8601. If you decode it directly (rather than via loadFromManifest), configure the decoder accordingly:

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601
let manifest = try decoder.decode(ScriptManifest.self, from: jsonData)