To calculate the vertices for a 3D NACA 0015 profile, one must first understand that NACA codes define 2D airfoil cross-sections, with the NACA 0015 indicating a symmetrical airfoil with 0 camber and 15% thickness. The 3D representation requires additional design considerations, such as blending between different airfoils from the root to the tip, as the NACA definition does not provide lateral dimensions. To create a 3D model in Gambit, the user needs to derive the 2D coordinates of the NACA 0015 profile and then determine how to transition these coordinates into three dimensions. The process involves calculating the vertices based on the chord length and thickness, followed by designing the blend line for the 3D shape. Ultimately, the detailed method for obtaining the vertices involves both mathematical calculations and design decisions.