This paper presents a process-based simulation toolkit CST and collaboration platform ProSIM to support planning of construction projects using simulation methods based on Building Information Modelling (BIM) and multi-model data exchange approaches. CST uses reference process models for construction activities and addresses data interoperability problems caused by the diversity of available CAD/BIM and project-planning software. The online collaboration platform connects design, planning, construction, and simulation experts together and enables an efficient communication and information sharing. This paper focus mainly on the collaboration and data interoperability aspects of CST and ProSIM in order to enable a wide adopting of simulation methods for planning of construction projects.