Mago3D is an open-source platform designed for visualizing large and complex 3D objects, integrating Building Information Modeling (BIM) with 3D Geographic Information Systems (GIS) in a web-based environment. It focuses on overcoming challenges in handling geospatial data through efficient algorithms for reducing file sizes and improving rendering speeds. The platform aims to evolve into a digital twin, allowing for real-time monitoring and analysis across varied applications in construction and urban management.