As most stars are born in a clustered mode, young massive star clusters are the best places to find and study the formation and evolution of massive stars. R136 is one of the most massive nearby clusters in the LMC. It contains at least 72 known O and Wolf-Rayet stars. These young stars are usually embedded in dust and gas so that correcting the local extinction plays an important role to estimate their mass from their luminosity. The extinction is derived for 26 O stars in different HST filters using TLUSTY model atmospheres of O stars. We derived the stellar masses, and hence the Mass Function (MF), using HST multi-color photometry. In parallel, we simulated series of R136-like clusters using the NBODY6 code to test the segregation scenario for R136. We could check whether massive stars are preferentially formed in the cluster core or formed homogeneously. By comparing the surface brightness profiles (SBP) of simulated clusters mimicking R136 with HST data, we could determine which scenario best represents R136. We present here a method that we used to connect the results of the NBODY6 simulations to R136 HST imaging data. The results of these studies bring a new insight to the understanding of R136 and similar clusters, pending future VLT and E-ELT high-contrast imaging observations at the diffraction limit at visible and IR wavelengths.