Another 555 system using the feature-based tracking technique is the mobile system for construction site visualization and interaction which was presented by Woodward et al [13]. As depicted in Figure 8, the system was validated in field tests, covering architectural augmented reality visualization with photo realistic rendering effects, up to construction time
applications at a real building site. This system software supported popular standard CAD/Cam
3D-formats, mixing them in real time by using GPS (Global Positioning System). The limitation of this research was that the 3D model building could not be rendered automatically. It had to be uploaded manually. Similar research for a mobile augmented reality framework that achieves scalability and accurate tracking can be also found in [14] by Ha et al.