If I have a finite set of points in 3D space, how would I decide which of these points constitute the "outer" points, that would, if plotted in 3D, appear to make up the surface of the point set?

More specifically, I am interested in the case where the points are regularly spaced, and whether there is a standard algorithm for this specific case, or a more general one for all cases?

Please see the attached image for an Example of what I mean.

Many thanks for any help!