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Skybolt Engine

Skybolt is a real-time planetary environment rendering engine, designed for flight simulators, aerospace R&D, and geospatial applications. Skybolt is written in C++, based on OpenSceneGraph, and supports CIGI for communicating with host applications. Skybolt also features a Python API for easy integration with science and engineering research tools.

The Skybolt repository includes Sprocket, a GUI application for creating scenarios and visualizing data. Sprocket supports python scripting and node-based graphical programming.

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  • Realistic environment rendering at multiple levels of detail, from orbit to planet surface
  • Tile streaming from geospatial data sources
  • Atmospheric scattering
  • Volumetric clouds
  • 3D Vegetation based on tree coverage data
  • FFT-based ocean wave simulation and rendering
  • Extensible entity component framework
  • CIGI support
  • JSBSim flight dynamics model integration
  • Bullet physics integration
  • Python API
  • Integrates with Sprocket R&D GUI platform, with node-based graphical programming system


Skybolt/Sprocket created and maintained by Matthew Reid. To submit a bug report, please raise an issue on the GitHub repository. For other queries, please use the contact form on the Piraxus website.


This project is licensed under the Mozilla Public License Version 2.0 - see the License.txt file for details.

Example Usage (C++)

// Create engine
auto params = EngineCommandLineParser::parse(argc, argv);
std::unique_ptr<EngineRoot> root = EngineRootFactory::create(params);

// Create camera
EntityFactory& entityFactory = *root->entityFactory;
World& world = *root->simWorld;
EntityPtr simCamera = entityFactory.createEntity("Camera");

// Attach camera to window
auto window = std::make_unique<StandaloneWindow>(RectI(0, 0, 1080, 720));
osg::ref_ptr<vis::RenderTarget> viewport = createAndAddViewportToWindowWithEngine(*window, *root);

// Create input
auto inputPlatform = std::make_shared<InputPlatformOis>(window->getHandle(), window->getWidth(), window->getHeight()));
std::vector<LogicalAxisPtr> axes = CameraInputSystem::createDefaultAxes(*inputPlatform);
root->systemRegistry->push_back(std::make_shared<InputSystem>(inputPlatform, window.get(), axes));
root->systemRegistry->push_back(std::make_shared<CameraInputSystem>(window.get(), simCamera, inputPlatform, axes));

// Create entities

EntityPtr planet = entityFactory.createEntity("PlanetEarth");

// Point camera at planet
auto cameraController = simCamera->getFirstComponentRequired<CameraControllerComponent>()->cameraController;

// Run loop
runMainLoop(*window, *root, UpdateLoop::neverExit);

Example Usage (Python)

import skybolt as sb

window = sb.StandaloneWindow(sb.RectI(0,0,800,600))
engine = sb.createEngineRootWithDefaults()

camera = engine.entityFactory.createEntity("Camera");

sb.attachCameraToWindowWithEngine(camera, window, engine)"SunBillboard"))"MoonBillboard"))"Stars"))

earth = engine.entityFactory.createEntity("PlanetEarth");

controller = camera.getFirstComponentOfType("CameraControllerComponent").cameraController

sb.stepOnceAndRenderUntilDone(engine, window, 0.1)

Projects and Dependencies

This repository contains multiple projects, described below, which can be enabled/disabled in CMake. Each project has a different set of dependencies. You only need to obtain dependencies for projects you wish to build. Header-only dependencies can be obtained from the SkyboltDependenciesHeaderOnly repository for convenience.

Skybolt Engine (Required)

The core engine libraries. Requires:

Skybolt Python Bindings

Python bindings for Skybolt. Requires:

Bullet Physics Engine Plugin

Skybolt plugin providing a rigid body dynamics component for entities by integrating the Bullet physics engine. Requires:

CIGI Plugin

Skybolt plugin providing a means for host applications to drive the simulation via the Common Image Generator Interface (CIGI). Requires:

FFT Ocean Plugin

Skybolt plugin simulating ocean waves with FFT. Requires:

JSBSim Plugin

Skybolt plugin providing an aircraft dynamics component for entities by integrating the JSBSim dynamics engine. Requires:


GUI application for creating, editing and running simulation scenarios, and performing analysis. Requires:

NodeGraph Plugin

Sprocket plugin providing a node-based graphical programming interface. Requires:

PythonConsole Plugin

Sprocket plugin providing an interactive python console in the Sprocket GUI.

Plot Plugin

Sprocket plugin providing a GUI for plotting graphs. Requires:

SequenceEditor Plugin

Sprocket plugin providing a GUI for editing animated sequences. Requires:

MapFeaturesConverter Tool

Application for converting Open Street Map data to Skybolt feature tile format.


Use CMake to configure and generate a build. Optional projects within the repository can be enabled/disabled with CMake BUILD_xxx properties as desired.

Installing Asset Packages

Skybolt requires runtime assets which are not included in this repository. Assets are split up into separate packages, which can be downloaded from

Only the Core package is required to run, but additional packages will add extra assets. To install a package, extract the zip file to a folder called "Assets" in the program working directory.


Working Directory

  1. Ensure the engine can find shaders (included in this code repository) under either Assets/Shaders or Source/Assets/Shaders relative to the working directory.
  2. Ensure the engine can find asset models under Assets/ relative to the working directory.


Engine settings are stored in a json file, which may be manually edited with a text editor, or edited in Sprocket with the Tools->Settings dialog. An example settings file template available at src/SkyboltExamples/ExamplesCommon/ExampleSettings.json.

The settings file can be loaded by example applications with the --settingsFile commandline option. If the option is not specified, a default Settings.json in the Operating System user's home directory will be used. On windows, this is located at C:/Users//AppData/Local/Skybolt/Settings.json.

Using third party Map APIs

By default, the PlanetEarth entity uses mapbox for albedo and elevation data. To use mapbox, you must acquire an API key from If desired, PlanetEarth can be edited to use Bing maps for albedo instead. A bing key can be obtained from Keys are stored in the engine json settings file (see above).