The GML is a real-time construct to design solution, proven to significantly improve the efficiency and quality control of tunnel construction. When utilised during various stages of the construction cycle, the system tracks and verifies as-built construction against the desired design in real-time. Given its fast computing and high-accuracy scan registration, the GML computes high-density BIM point cloud data in real time. This gives users high-resolution 3D information of the current construction against the desired design profile. Highly accurate, detailed information such as overbreak, underbreak and shotcrete thickness is provided live to tunnelling crews with no manual processing. Real-time feedback allows crews to verify their construction and to make calculated decisions in real time to increase efficiency, save time and cost, and reduce rework with every advancement.