Export and import using the .3MF format with Multi-Surface and RGBA Support in InVesalius

This project focuses on adding full 3MF export and import support to InVesalius, enabling efficient handling of multi-surface medical models with accurate color (RGBA) representation and proper coordinate transformations. At present, InVesalius does not support modern 3D formats like 3MF, which offer better structure, metadata handling, and color capabilities compared to formats such as STL and OBJ. Through this project, I aim to integrate 3MF support into the existing export and import pipeline using lib3mf, ensuring compatibility with tools like OrcaSlicer while preserving geometry, scaling, and visual attributes. The implementation will handle coordinate transformations (LPS ↔ Z-up), support multi-surface models, include alpha channel handling, and integrate cleanly with the current architecture. This work builds on my prior contributions to InVesalius, where I have worked on surface pipelines, coordinate transformations, and UI workflows, allowing me to integrate this feature effectively within the existing system. The goal is to improve interoperability with modern 3D tools, ensure accurate representation of models, and provide a solid foundation for future extensions in 3D medical imaging workflows.