3D surfaces can also be drawn using solid pm3d quadrangles rather than
lines. In this case there is no hidden surface removal, but if the component
facets are drawn back-to-front then a similar effect is achieved.
See set pm3d depthorder (p. ). While pm3d surfaces are by default colored using a
smooth color palette (see set palette (p. )), it is also possible to specify a
solid color surface or to specify distinct solid colors for the top and bottom
surfaces as in the figure shown here. See pm3d fillcolor (p. ).
Unlike the line-trimming in hidden3d mode, pm3d surfaces can be smoothly
clipped to the current zrange. See set pm3d clipping (p. ).