Modelling material which includes (a) at least one radically polymerizable monomer, (b) at least one initiator for the radical polymerization and (c) at least one inert component. The inert component (c) is soluble in the polymer formed by polymerization of the monomer (a), wherein the solubility of component (c) decreases as the temperature increases, with the result that a phase separation takes place above a particular temperature. The material is suitable in particular for the production of models of dental restorations for investment casting processes.