Mark Horgan developed enhancements for the ViveportSoftware/pc-lib repository, focusing on polygon streaming animation playback and state mapping. He introduced new TypeScript attributes that allow for precise control over animation playback, including support for automatic playback, specific animation names, and animation state graph identifiers. By refining attribute descriptions and improving state mapping, Mark enabled more dynamic and configurable 3D graphics models. His work emphasized configuration management and front-end development, ensuring that both new and existing attributes were clearly documented. The depth of these changes improved developer experience and expanded the flexibility of polygon streaming within the project’s animation system.