The simulation of sand gravity casting process is one of the complicated processes due to the multiscale & metaphysics. Even though some commercial software is available, it is extremely difficult to predict the exact defects induced by filling and solidification. In particular oxidation prediction requires tracking the fluid front and where it oxides which is not feasible with mesh-based methods. Smoothed particle hydrodynamics (SPH) is a Lagrangian simulation approach that is particularly well adapted to modeling filling, cooling, and solidification of the gravity casting process. This work aims to investigate the filling, cooling, and solidification phases of the closed gravity casting of AlSi13 in resin-bonded sand molds using experimental and numerical approaches (SPH and commercial software) in order to evaluate and compare 2D and 3D results. Firstly, a universal experimental test case of the gravity casting process is designed that can be modeled in 2D in terms of filling, cooling, and solidification. This is regarding the validation of the 2D gravity casting SPH code for a closed gravity casting system. Secondly, the SPH code is upgraded to 3D, and the results of the filling, cooling, and solidification have been studied in the case of a more realistic 3D casting with an experiment using transparent glass. Finally, simulation of the filling, cooling, and solidification steps of the sand gravity casting process using SPH methodology in 2D and 3D along with experimental validation provides the basis for predicting defects like oxidation.