Dislocation dynamics are important to understand material plasticity in small-sized materials. In case of face-centered cubic crystalline systems, densities of initial dislocations, dislocation nucleations and starvations processes influence material strengths at micro- and nano-scales [1]. To model these multi-scale physics in concurrent manners, 2D Coupled Atomistic and Discrete Dislocation dynamics (CADD) [2] is the only available computational tool. However, in CADD, the described dislocation dynamics are limited to 2 dimensional systems. In this presentation, we propose a new method for coupling MD and DD simulations in 3D (CADD3D) to resolve the limitations of CADD. We introduce its required building blocks (core templates [3] and mobility law) and the coupling-communication scheme. The dynamics of a hybrid dislocation, which is a dislocation structure composed of atomic and discrete dislocations, will be shown to demonstrate the workability of the proposed communication scheme. Furthermore, several applications will be presented using CADD3D such as an expanding dislocation loop nucleated from a Frank-Read source.