In this work, selective area growth has been used for the realization of InP based photonic integrated circuits (PICs). To predict the strain, thickness and bandgap energy variations over large and high-density multifunctional arrays, it is necessary to precisely design the shapes and positions of the dielectric masks by computational modeling. To address the mask layout density and complexity in both longitudinal and transversal direction, the use of three dimensional vapor phase model was mandatory. In each SAG region used for individual component processing, the calculated data were compared to experimental ones acquired by synchrotron-based microbeam x-ray diffraction and by micro-photoluminescence wavelength mapping. The excellent result concordance shows that both advanced modeling and characterization techniques are of importance for PIC conception and fabrication.