functions in pl3d.i - l

    light3, ambient=a_level,  
    diffuse=d_level,  
    specular=s_level,  
    spower=n,  
    sdir=xyz  


  Sets lighting properties for 3D shading effects.  
  A surface will be shaded according to its to its orientation  
  relative to the viewing direction.  
  The ambient level A_LEVEL is a light level (arbitrary units)  
  that is added to every surface independent of its orientation.  
  The diffuse level D_LEVEL is a light level which is proportional  
  to cos(theta), where theta is the angle between the surface  
  normal and the viewing direction, so that surfaces directly  
  facing the viewer are bright, while surfaces viewed edge on are  
  unlit (and surfaces facing away, if drawn, are shaded as if they  
  faced the viewer).  
  The specular level S_LEVEL is a light level proportional to a high  
  power spower=N of 1+cos(alpha), where alpha is the angle between  
  the specular reflection angle and the viewing direction.  The light  
  source for the calculation of alpha lies in the direction XYZ (a  
  3 element vector) in the viewer's coordinate system at infinite  
  distance.  You can have ns light sources by making S_LEVEL, N, and  
  XYZ (or any combination) be vectors of length ns (3-by-ns in the  
  case of XYZ).  (See source code for specular_hook function  
  definition if powers of 1+cos(alpha) aren't good enough for you.)  
  With no arguments, return to the default lighting.  
EXAMPLES:  
  light3, diffuse=.1, specular=1., sdir=[0,0,-1]  
    (dramatic "tail lighting" effect)  
  light3, diffuse=.5, specular=1., sdir=[1,.5,1]  
    (classic "over your right shoulder" lighting)  
  light3, ambient=.1,diffuse=.1,specular=1.,  
          sdir=[[0,0,-1],[1,.5,1]],spower=[4,2]  
    (two light sources combining previous effects)  
  Interpreted function, defined at i/pl3d.i   line 262  

    limit3, xmin,xmax, ymin,ymax  
 or limit3, xmin,xmax, ymin,ymax, zmin,zmax  


Set the 3D axis limits for use with the cage.  
Use keyword aspect=[ax,ay,az] to set the aspect ratios of the  
cage to ax:ay:az -- that is, the ratios of the lengths of the  
cage axes will become ax:ay:az.  
Interpreted function, defined at i/pl3d.i   line 181