#### 10.11.7 DrawSmoothFacet

• draw("SmoothFacet", facets1, [options1], facets2, [options2], ... )
• Description: that macro sort the set of all the facets and displays them according to their options but the eventual intersections are not handled.with exports in pstrick or eps, and then epsc and pdf and (but not pdfc), the GOURAUD algorithm is used to fill the facets (after triangulation) that is giving a smoothing effect, the smoothin is not visible on screen. With that macro the edges are not drawn. Options are:
• backculling := < 0/1 >. Shows if the hidden facets have to be eliminated or not (0 par défaut).
• color := < color >. Setting the color (white by default).
• contrast := < positive number >. The ordinary contrast is $1$ (default value), a contrast set to zero means the color is solid.
• That macro uses a personalized export and then can be used in the form draw("SmoothFacet",facets1, [options1], facets2, [options2], ... ), with that form, the export will automatically launch the execution of the macro macro ExportSmoothFacet() that is defined in the file scene3d.mac. While in the form DrawSmoothFacet(facets1, [options1], facets2, [options2], ... ) the export will be classic export, that is what can be seen on screen (facets without smoothing).

 \begin{texgraph}[name=DrawSmoothFacet,                    export=eps]   Marges(0,0,0,0),size(7.5),   background(full,beige),   draw("SmoothFacet", Sphere(M(-3,0,0),3,25,15),                     [color:=steelblue,                      backculling:=1],                    Sphere(M(3,0,0),3,25,15),                     [color:=orange])   \end{texgraph}

Example with DrawSmoothFacet

Warning: the above example illustrate the macro DrawSmoothFacet that permits to smooth the facets with the GOURAUD algorithm. But that algorithm is really known only by ghostscript. That is why pdf rendering takes sometimes long time (very long time) and not accurate for big images. In that case, it is preferable to get a high resolution jpeg (or an eps export if the document has to stay using ps format).