1. Introduction
- Briefly explain what Three.js is and why debugging can be tricky in 3D applications.
- State the goal: help developers quickly identify and fix common problems.
2. Common Issues and Fixes
a. Scene Not Rendering
- Check if the renderer is attached to the DOM.
- Ensure the camera is positioned correctly and pointing at the scene.
- Verify that
requestAnimationFrame()is being called.
b. Objects Not Visible
- Confirm lights are added to the scene.
- Check object position (it may be outside the camera view).
- Verify material settings (e.g., transparent objects with opacity
0).
c. Textures Not Loading
- Check the file path or server configuration (CORS issues).
- Use
.setPath()when loading multiple assets. - Test with a placeholder material to confirm the geometry is loading.
d. Performance Issues (Laggy/Low FPS)
- Reduce polygon count in models.
- Use texture compression.
- Enable frustum culling and use
InstancedMeshwhen possible.
e. Shader Errors
- Validate GLSL syntax.
- Use browser console logs to identify line numbers.
- Test with a simpler shader, then add complexity step by step.
3. Debugging Tools for Three.js
- Browser DevTools → Monitor console errors, performance, and WebGL context.
- Stats.js → Track FPS and performance bottlenecks.
- dat.GUI / lil-gui → Tweak parameters live to test changes.
- Three.js Inspector → Chrome extension for inspecting scenes.
4. Best Practices for Troubleshooting
- Start with a minimal reproducible example.
- Check the Three.js version (breaking changes between releases).
- Read the console errors carefully — they often point to the issue.
- Incrementally add complexity to isolate the problem.
5. Conclusion
- Summarize the most common issues.
- Encourage developers to use community forums (e.g., Three.js Discourse, Stack Overflow) when stuck.
- Link to official Three.js docs for deeper reference.