Module slice3.py contains two plotting functions of interest. First, pl3surf can be used for graphing surfaces on an arbitrary two-dimensional mesh with filled cells and no mesh lines. (Currently plwf can be used to do the same thing in the case of a mesh all of whose cells are quadrilateral, and has more flexibility, in that it allows mesh lines to be drawn and/ or allows for the mesh to be see-through.) Secondly, pl3tree is a plotting function that can be called multiple times in order to have several surfaces drawn on the same graph. pl3tree (as its name suggests) creates a tree of values sorted as to when they will be plotted on the screen; if the algorithm works correctly, then more distant cells are plotted first, then covered by closer cells which are plotted later, giving the surface the correct appearance.
Surfaces to be plotted by pl3surf or pl3tree can be generated by taking plane sections of an arbitrary mesh or by creating isosurfaces for some function or functions defined on the mesh. These planes and isosurfaces can themselves be sliced and portions discarded, to enhance visibility of the interior. The functions mesh3 and slice3mesh take raw input data and put it into the form accepted by slice3, which can form plane sections or isosurfaces through the mesh. Functions slice2 (which returns the portion of a surface in front of the slicing plane) and slice2x (which returns the two parts of a surface sliced by a plane) complete the triumvirate of slicing functions.
The algorithms in slice3 are independent of the underlying graphics. Thus slice3 may equally well be used with Narcisse graphics.