The starting point for building a ConstructSim Planner Virtual Construction Model (VCM) is the 3D CAD data. Currently, ConstructSim Planner supports PDS, CIS/2 and most i-model formats (through an i-model mapping adapter). Examples of current certified i-model formats are PDMS, OpenPlant, and PlantSpace Design Series. This stage contains an important function whereas the CAD model must be analyzed for the relevant data it contains. It is important that the model(s) contain valid identifiers applicable to the project, for example, Pipeline Identifiers, Equipment tags, etc. This affects all downstream data integration as these identifiers will be used to link secondary data to the objects in the CAD model. For example, if a CAD model has a large amount of piping objects in it, but there is no single common attribute with which to identify a pipeline, or a pipe spool, this adds greater complexity to associating data to the model at later stages. In the same way, importing Schedule and Materials data later on needs to be associable with objects (or collections of objects) in the model.