USDKit Framework

import USDKit
import Foundation

@main
struct USDSceneComposer {
    static func main() async throws {
        // 1. Open an existing USD stage from disk
        let sceneURL = URL(filePath: "/tmp/workbench.usda")
        let stage = try USDStage.open(sceneURL)

        // 2. Traverse existing prims to check for our asset
        var foundOscilloscope = false
        for prim in stage.traverse() {
            if prim.path.string.contains("oscilloscope") {
                foundOscilloscope = true
                break
            }
        }

        // 3. If not found, define a new transform prim and reference the asset
        if !foundOscilloscope {
            let primPath = USDPath("/Workbench/Oscilloscope")
            let xformPrim = stage.definePrim(at: primPath, type: "Xform")

            let assetURL = URL(filePath: "/tmp/assets/oscilloscope.usda")
            xformPrim.addReference(USDReference(assetPath: assetURL.path))

            // 4. Move the prim onto the workbench
            let translateOp = xformPrim.addTransformOperation(
                type: .translate,
                precision: .double
            )
            try translateOp.set(value: SIMD3<Double>(0.0, 0.85, 0.0))

            // 5. Apply accessibility schema and set label + description
            xformPrim.applySchema(named: "AccessibilityAPI")
            let labelAttr = xformPrim.createAttribute(
                named: "accessibility:label",
                type: .string
            )
            let descAttr = xformPrim.createAttribute(
                named: "accessibility:description",
                type: .string
            )
            try labelAttr.set(value: "Oscilloscope")
            try descAttr.set(value: "A vintage analog oscilloscope sitting on the workbench, used for measuring electrical signals.")
        }

        // 6. Export a compressed package (mesh + texture compression)
        let outputURL = URL(filePath: "/tmp/workbench_compressed.usdz")
        var options = USDExportOptions()
        options.compressMeshes = true
        options.compressTextures = true
        try await stage.exportPackage(to: outputURL, options: options)

        print("Export complete: \(outputURL.path)")
    }
}