// A grid on the Y-Z plane
// Last edited on 2005-08-28 11:07:44 by stolfi

#macro grid(nx, nz, h)
  #local rad = 0.005;
  union {

    #local iz = -nz;
    #while (iz <= nz) 
      #local cz = iz*h*z;
      #local wx = nx*h*x;
      cylinder { cz - wx, cz+wx, rad }
      #local iz = iz + 1;
    #end

    #local ix = -nx;
    #while (ix <= nx) 
      #local cx = ix*h*x;
      #local wz = nz*h*z;
      cylinder { cx - wz, cx+wz, rad }
      #local ix = ix + 1;
    #end

    texture { 
      pigment { color rgb < 0.750, 0.250, 0.000 > } 
      finish { ambient 1.00 diffuse 0.00 }
    }
  }
#end