Thermion is a framework for creating cross-platform 3D applications with Dart and/or Flutter.

Overview#

Below is a general overview of how the Thermion packages are structured to ensure a clean separation between the general Dart components, and the Flutter specific components.

If you want a more detailed explanation of how to start rendering 3D content inside a Flutter app, click here to view the quickstart page.

Package structure #

Thermion is divided into two packages:

• thermion_flutter, a Flutter package for creating/embedding a rendering surface inside a Flutter app. 
• thermion_dart, which contains all the code needed to create a viewer.

With this structure, the Flutter-specific components are not coupled to the Dart components, meaning Thermion can be used for rendering in both Flutter and non-Flutter applications.

For example, Thermion ships with examples for rendering with Dart only (no Flutter) with a CLI/headless application on MacOS, and with a Javascript/WASM/HTML applicaiton in browsers.

thermion_flutter exports thermion_dart, so if you are working with a Flutter application, you will only need to import thermion_fluttter.

ThermionViewer (thermion_dart)#

The ThermionViewer class provides an API for creating and interacting with 3D scenes powered by the Filament rendering engine.

It allows loading 3D models in glTF format, adding lights and a skybox, manipulating the camera, animating objects, and more.

Key functionalities include:

• Scene Management: Load and manipulate entities, lights, skyboxes, and background elements within a 3D scene.
• Rendering Control: Manage rendering loop, frame rate, and post-processing effects like tone mapping and bloom.
• Camera Control: Position and orient the camera, adjust focal length, and control exposure settings.
• Animation: Play, pause, and manipulate skeletal and morph target animations.
• Entity Manipulation: Transform entities (position, rotation, scale), set material properties, and manage parent-child relationships.
• Collision Detection (experimental): Add collision components to entities and test for collisions within the scene.
• Input Handling: Interact with the scene using touch gestures for panning, rotating, and zooming.
• Developers use the ThermionViewer class to build and control the behavior of their 3D applications.

ThermionFlutterPlugin#

The ThermionFlutterPlugin class handles the platform-specific initialization required to embed a Filament rendering surface within a Flutter Widget.

This includes creating a texture and managing the application lifecycle to pause rendering when the app is inactive.

You will generally only need to interact with ThermionFlutterPlugin directly to create or dispose of a ThermionViewer.

ThermionWidget (thermion_flutter)#

ThermionWidget is a Flutter widget that displays the 3D content rendered by a ThermionViewer.

It handles creating and managing the underlying platform-specific texture that Filament renders to, and provides a way to embed this texture within the Flutter widget tree.

Key features of ThermionWidget include:

• Texture Management: It creates, resizes, and destroys the ThermionFlutterTexture used to display the rendered content from the ThermionViewer.
• Platform Adaption: It handles platform-specific differences, such as texture coordinate systems, to ensure consistent rendering across different platforms.
• Initialization Handling: Displays a placeholder (configurable via the initial property) while the Filament texture is being initialized, providing a smoother user experience.
• Seamless Integration: Integrates seamlessly within the Flutter widget tree, allowing developers to combine 2D and 3D content easily.
• Resize Handling: It listens for resize events and automatically resizes the underlying texture to match, ensuring the 3D content scales correctly.