Abstract: An improved method for design and testing using a CAD system incorporating the automatic production of a bloc-structured hexahedral grid of a mathematically defined volume from a previously generated surface definition of the volume. A surface definition of an object is designed and stored in a CAD format, then numerically scanned to detect major geometric features. A structured, hexahedral grid is projected through the volume with a grid density and spacing conforming to the major geometric features of the surface definition. All grid elements which do not intersect the volume within surface definition are discarded, and the remaining surface nodes are projected onto the surface definition of the volume. Highly distorted elements resulting from the projection are minimized by iteratively smoothing nodes on the corners, edges, and surfaces of the surface definition by applying a relaxation algorithm.