How to automatically select the outermost points in 3d & make a volume

i tried convex hull but it does not work in the xyz plane, mesh points only but it is a single plane, manually picked & meshed the points, subdfriendly and loft it but it also doesnt work

exe3 (48.1 KB)

exe 3 grids 001 without loft connected.3dm (1.5 MB)

3D ConvexHull ?