The invention is directed to a process of manufacturing a three-dimensional object by—providing a support structure comprising polyvinyl alcohol (PVOH) to—depositing and solidifying a molten thermoplastic polymer on the support structure to form a three-dimensional preform characterized in that the support structure consists of a mixture of polyvinyl alcohol (PVOH) and at most 20% by weight of at least one plasticizer according to formula (I), (II) or (III): —R1-C(CH2—OH)3 (1); —[R1-C(CH2—OH)2CH2]2O (11); —(R1)C(CH2—OH)2CH2—O—CH2C(CH2—OH)C(R1)CH2—O—CH2 C(CH2—OH)2R1 (III). With R1=H, CH3, C2H5, C3H7, CH2OH. The support structure can be dissolved to from the three-dimensional object.