Generating virtual environments of real world facilities: Discussing four different approaches

There is an increasing need to generate detailed real-time virtual environments that closely mimic real world facilities. Approaches for the generation of virtual environments can be manual, automatic, or hybrid. Manual approaches are time consuming, inaccurate, and coarse whereas automatically generated data sets are less than optimal for practical use within real-time virtual environments because of the huge unstructured amount of data. Therefore, common approaches are most likely to have a balance between human and computer effort. Based on different projects, we discuss possible distributions of manual and automatic methods for the generation of 3D virtual environments. We present different facets of the pipeline from initial data gathering up to the final deliverable. The approaches employed in these projects vary from fully hand made up to semi-automatic reconstruction of the environments. The paper concludes with recommendations regarding the reconstruction methods.