OpenSKP — Pure Dart SketchUp Binary Parser

OpenSKP is a pure Dart library designed to parse SketchUp (.skp) binary files directly in Dart and Flutter applications without requiring any native Trimble SketchUp SDK dependencies.

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🌟 Vision & Platform Coverage

Enable mobile (iOS/Android), desktop, and web developers to parse and build 3D SketchUp file viewer pipelines natively inside Flutter.

• Mobile: Flutter iOS & Android apps
• Desktop: Flutter Windows, macOS, and Linux
• Web: Compile client-side for browser-based parsers
• Server: Dart shelf backend parsing services

🌐 Try the Live Web Viewer (Drag-and-Drop)

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✨ Features

• Zero Native Dependencies: 100% pure Dart implementation.
• TLV Binary Decoding: Decodes SketchUp's internal Tag-Length-Value records.
• VFF ZIP Extractors: Decompresses and validates VFF file containers to extract model.dat and material XML assets.
• Geometry & Hierarchy: Recovers vertices, edges, face loops, component definitions, and nested instance transformations.
• Steelframer properties: Reads custom dynamic component attribute values.

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🚀 Installation

Add the library to your Dart or Flutter project:

# For Dart projects
dart pub add openskp

# For Flutter projects
flutter pub add openskp

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💻 Quick Start

1. Parsing a SketchUp File

Open a .skp file, read the byte buffer, and load the data model:

import 'dart:io';
import 'package:openskp/openskp.dart';

void main() async {
  // Read SKP file bytes
  final file = File('my_model.skp');
  final bytes = await file.readAsBytes();

  // Load and parse SKP model
  final skpFile = SkpFile.fromBuffer(bytes);
  final model = skpFile.parse();

  print('SketchUp File Version: ${model.version}');

  // Inspect Layers
  print('Layers:');
  for (var layer in model.layers) {
    print('- ${layer.name} (RGB: ${layer.colorR}, ${layer.colorG}, ${layer.colorB})');
  }

  // Inspect Materials
  print('Materials:');
  for (var material in model.materials) {
    print('- ${material.name} (Opacity: ${material.transparency})');
  }

  // Walk component definitions and their geometry
  model.definitions.forEach((id, def) {
    print('Definition $id: ${def.name} - ${def.vertices.length} vertices, ${def.faces.length} faces');
  });

  // model.root holds whatever is placed directly in the model (not inside
  // any component/group), including root-level instances.
  print('Root-level instances: ${model.root.instances.length}');
}

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📐 API Data Model Reference

The public API is designed to mirror the Python reference implementation's data model (the same shape the C# port also follows):

SkpModel

• String version — The parsed SketchUp application version.
• Map<int, Definition> definitions — Component/group geometry definitions, keyed by their numeric TLV entity ID.
• Definition root — Whatever is placed directly in the model (not inside any component/group).
• List<Layer> layers — Layer names and color configurations.
• List<Material> materials — Material names, color channels, and transparency values.
• Map<int, Material> materialsById — Join table from a TLV material ID (Face.materialId) to its Material.
• List<Style> styles — Bundled rendering styles (default front/back face colors).

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📄 License

This library is open-source software licensed under the MIT License — see the LICENSE file for details.