After main ideas and concepts regarding building simulator have been presented, more technical details regarding this topic have been presented within the last lecture. An overview of the available building simulator approaches has been given and it was illustrated how building simulator could be developed within web based service, with the specifics regarding the architecture choices. One of the proposed solutions has been developed using JavaScript (JS), showing the advantages over the conventional simulators. Final approach that has been presented covered distributed computing using cloud based solution and FMI standard.