I have DEM Data which is in SHP Format. After interpolating to raster, I need to clip the raster image. To do this, I need to transform the Point SHP into a Polygon SHP using only the outer-most points to create the polygon. A Convex Hull does not produce the required results as shown in the diagram - The red outline is the Convex Hull. The arrows show the areas which should also be clipped.

I Have FME and ArcGIS Advanced.