A building of the future will have a perfect knowledge of its functionality, including energy efficiency, and will respond in terms of health, comfort and sustainability, on changes in occupancy, weather and operating conditions. The Building Digital Twin concept combines 3D geometrical information with a functional mathematical model, which may be used in all phases of construction, during commissioning, and for real time control during exploitation. To get this happen it is necessary to develop ready to use standardized components, which are called SIMBOTS at BDTA (Building Digital Twin Association). The objective of SIMBOTs development is to have a semantic neutral representation of equipment’s and other entities playing in real time simulation of a building. At the Hycool-IT project, a pilot of a data center has been used as initial sand box for testing. Several different simulation software have been used to compare methodologies. A number of SIMBOTs for a pilot data center will be presented, with the problems found in the possible standards for real time, and discussed together with software developers looking for feedback and improvements.