Growth of InGaAs/InP heterostructures on patterned (100) InP substrates by metalorganic vapor-phase epitaxy (MOVPE) was investigated. Anisotropic growth rates as obtained by measurements were exploited to precisely predict defined growth shapes. We present a model with a complete set of parameters to simulate the growth of In0.53Ga0.47As and InP by MOVPE. The model relies on a graphical construction procedure to determine the cross-sectional structure of heterostructures on patterned substrates.