functions in plwf.i -

             lightwf, cmax  
 
     Sets the cmax= parameter interactively, assuming the current  
     3D display list contains the result of a previous plwf call.  
     This changes the color of the brightest surface in the picture.  
     The darkest surface color can be controlled using the ambient=  
     keyword to light3.  

             plwf, z  
          or plwf, z, y,x  
 
     plots a 3-D wire frame of the given Z array, which must have the  
     same dimensions as the mesh (X, Y).  If X and Y are not given, they  
     default to the first and second indices of Z, respectively.  
     The drawing order of the zones is determined by a simple "painter's  
     algorithm", which works fairly well if the mesh is reasonably near  
     rectilinear, but can fail even then if the viewpoint is chosen to  
     produce extreme fisheye perspective effects.  Look at the resulting  
     plot carefully to be sure the algorithm has correctly rendered the  
     model in each case.  
   KEYWORDS: fill   -- optional colors to use (default is to make zones  
                       have background color), same dimension options as  
                       for z argument to plf function  
             shade  -- set non-zero to compute shading from current  
                       3D lighting sources  
             edges  -- default is 1 (draw edges), but if you provide fill  
                       colors, you may set to 0 to supress the edges  
             ecolor, ewidth  -- color and width of edges  
             cull   -- default is 1 (cull back surfaces), but if you want  
                       to see the "underside" of the model, set to 0  
             scale  -- by default, Z is scaled to "reasonable" maximum  
                       and minimum values related to the scale of (X,Y).  
                       This keyword alters the default scaling factor, in  
                       the sense that scale=2.0 will produce twice the  
                       Z-relief of the default scale=1.0.  
             cmax   -- the ambient= keyword in light3 can be used to  
                       control how dark the darkest surface is; use this  
                       to control how light the lightest surface is  
                       the lightwf routine can change this parameter  
                       interactively