Abstract: An apparatus and method of fabricating a three-dimensional model which reduces occurrence of one a hairline crack(s), stress fracture(s), break(s), flaw(s) and/or other imperfection(s) in the final three-dimensional model. The method comprising the steps of selecting the model material, selecting the sacrificial material, and adding at least one additive to the sacrificial material for at least one of increasing the thermal conductivity, decreasing a coefficient of thermal expansion or decreasing an ability of the sacrificial material to transmit stress to the model material. The three-dimensional composite model is built by depositing a plurality of layers one on top of another.