Numerical relativity simulations can be used to describe the spacetime evolution during nonlinear structure formation in ΛCDM cosmology. To do this, I have set fully nonlinear initial conditions of a simple 3-D sinusoidal structure, this creates a lattice of quasi-spherical over-densities representing idealised dark matter halos connected through filaments and surrounded by voids. I have then evolved this with the Einstein Toolkit code using a pressureless perfect fluid (dust) description of matter. To present the results of this simulation, I will draw comparisons with the top-hat spherical and homogeneous collapse model. Then I will introduce different methods to characterise spacetime, namely Gravitoelectromagnetism and the Petrov classification and I will show what these methods reveal about the relativistic effects present in the simulation.