#### 3.25.53.6 hidden3d

The option hidden3d draws the bounding lines of each quadrangle at the same time that the quadrangle itself is drawn. Normally it is used in conjunction with the ‘depthorder‘ option to achieve an approximation to true hidden line removal. This is far more efficient than using the command hidden3d. The command takes an optional linestyle controlling the appearance of the bounding lines. If the linestyle parameter is negative, or omitted, then the line properties given in the plot command are used. Example of recommended usage:

          set pm3d at s hidden3d depthorder
          unset hidden3d
          unset surf
          splot x*x+y*y linecolor rgb "black" linewidth 0.5