Compared to the two-dimensional one, the three dimensional deployment in WSNs (wireless sensor networks) is more complex and real. In this paper, the problem of 3D positioning of nodes is studied while minimizing the number of nodes and the consumption of energy; and maximizing the coverage area and the localization rate. Indeed, the aim is to choose the ideal 3D positions in which new nodes are added while optimizing the mentioned objectives. The proposed approach is based on two evolutionary algorithms (MOEA/D and NSGA-III). The simulation model takes into account the implementation of a 433 MHz physical layer, a non-coordinated IEEE 802.15.4 CSMA/CA access method, and a reactive AODV based protocol for routing layer. The obtained results of the simulations with OMNeT++ are presented to prove the effectiveness of the proposed approach.