Process of photopolymer stereo-lithography (SLA) provides a unique opportunity for rapid prototyping  of high surface quality and complex geometry investment castings from ferrous and non-ferrous metals. A specific internal honeycomb structure gives a combination of high pattern stiffness needed for precise replication of geometry by investment shell molds with an extremely lightweight of pattern which minimizes a residual after pattern removal. In this article, the thermo-mechanical properties of SLA patterns (coefficient of thermal expansion, modulus, softening and decomposition temperatures) were experimentally evaluated. It was shown that anisotropy of thermo-mechanical properties of SLA pattern depends on orientation of the honeycomb structure. A novel approach for FEM modeling of anisotropic SLA patterns was suggested and verified using experimental data. Coupling thermo-mechanical pattern/ceramic shell modeling was used to predict stress in the ceramic shell during pattern removal and tendency for crack formation. Experiments were performed to verify modeling predictions.  Recommendations for optimal structure of SLA pattern for investment castings were formulated.