A review of the state-of-the-art in object-oriented modelling of virtual-labs for control education is presented. The presentation emphasizes the main advantage of this methodology: the reduction in the modelling effort. The combined use of different languages and tools is addressed: Modelica/Dymola, Sysquake, Easy Java Simulations (Ejs) and Matlab/Simulink. In particular, three approaches to virtual-lab implementation are discussed. The Modelica language is used in all of them for describing the model and Dymola is used for translating the model into executable code. For the first approach,...