We present a single block adaption strategy for 3-D cartesian grids. The adaption process proceeds as an interface with the PHOENICS package. It allows continuous runs or unsteady calculations by reconstructing the interpolated solution on the new mesh at each adaption step. To perform the adaption, we define a new metric based on and proportional to the Hessian of the unknown variables. The adapted grid is defined by equidistributing the nodes. The interpolated solution is computed by using its barycenter coordinates together with its first order partial derivatives.