OCCTSwiftViewport documentation

A reusable Metal-based 3D viewport for CAD applications on iOS 18+ / macOS 15+ / visionOS — camera control, GPU picking, PBR lighting, measurement overlays, and a headless offscreen renderer. It is the rendering companion to OCCTSwift: the two libraries are fully independent — OCCTSwiftViewport knows nothing about OCCT or B-Rep topology; your app bridges geometry into a ViewportBody and the viewport displays it.

import SwiftUI
import OCCTSwiftViewport

struct ContentView: View {
    @StateObject private var controller = ViewportController()

    // Bodies live in @State so SwiftUI owns the binding the view renders.
    @State private var bodies: [ViewportBody] = [
        .box(id: "box", width: 2, height: 2, depth: 2,
             color: SIMD4(0.4, 0.7, 0.95, 1)),
    ]

    var body: some View {
        MetalViewportView(controller: controller, bodies: $bodies)
    }
}

Cookbook

Task-oriented, example-rich guides — each a short bit of prose plus runnable Swift, with a rendered figure where it helps. The Cookbook index lists all areas:

Getting Started · Display Modes · Camera & Navigation · ViewCube · Lighting & Materials · Picking & Selection · Loading Geometry · Measurements · Clip Planes & Sections · Offscreen Rendering · Gestures & Input · HUD Overlays

Reference

• API Reference — the detailed, per-type function reference: every public type and member, signatures, parameters, and runnable examples, grouped by domain (camera, picking, rendering, materials, measurement, …).
• Changelog — release-by-release history.

Architecture & concepts

• Metal Architecture — the render pipeline, pick texture, shadow/IBL passes.
• The library is @MainActor-isolated for mutable state holders (ViewportController, CameraController, ViewportRenderer); value types and configs are Sendable. Swift 6 ready.

Where it fits

Your App
  ├── OCCTSwift          (geometry kernel — B-Rep, STEP, booleans, …)
  ├── OCCTSwiftViewport  (Metal rendering, camera, picking — no OCCT dependency)
  ├── OCCTSwiftTools     (Shape → ViewportBody bridge, file I/O, export)
  └── displays geometry in the viewport

See the ecosystem map for how this package relates to the kernel, bridge, and sibling layers.

Project

• Source & issues: github.com/gsdali/OCCTSwiftViewport
• Install via Swift Package Manager — pin from: "1.0.0" (SemVer-stable since v1.0.0).
• Requires iOS 18+ / macOS 15+, Swift 6.0+, Xcode 16+.