Three.js Model Format Conversion

Based on the Three.js documentation, you can use a combination of loaders and exporters to convert between different 3D model formats. Here's what you need to know:

Available Exporters

Three.js provides several exporters that can help with your conversion needs:

• GLTFExporter
• OBJExporter
• DRACOExporter
• EXRExporter
• PLYExporter
• STLExporter

Available Loaders

For importing your models, Three.js offers these loaders:

• GLTFLoader (for GLB/GLTF files)
• OBJLoader
• MTLLoader (for materials with OBJ)
• DRACOLoader
• 3DMLoader
• FontLoader
• KTX2Loader
• LDrawLoader
• And others

Conversion Process

The general approach would be:

1. Load the source model using the appropriate loader
2. Export the loaded model using the desired exporter

Limitations

Based on the available documentation, there are some important limitations to consider:

1. FBX to GLB Conversion: There's no direct FBXExporter in the standard Three.js library, which means you can import FBX but not directly export to it. You would need a third-party solution for FBX export functionality.

2. Format Compatibility: Different formats support different features. When converting between formats, you might lose certain data:

   • Materials and textures might not transfer perfectly
   • Animations might be lost or altered
   • Custom properties specific to certain formats might not be preserved

3. GLB Specifics: GLB is a binary format of GLTF that can include textures and animations in a single file. When converting to OBJ, you might need to handle textures separately.

For your specific use case, you can use:

• GLTFLoader to load GLB files
• OBJLoader to load OBJ files
• OBJExporter to export to OBJ format

However, for FBX export functionality, you would need to look beyond the standard Three.js library as there is no built-in FBXExporter mentioned in the documentation.