From 3ef72093ee5d919e0aabb8339f834023028db646 Mon Sep 17 00:00:00 2001 From: wolf Date: Tue, 19 Jan 1999 15:54:09 +0000 Subject: [PATCH] Add doc for conventions of faces, lines and vertices in 3D. git-svn-id: https://svn.dealii.org/trunk@738 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/deal.II/include/grid/tria.h | 91 +++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) diff --git a/deal.II/deal.II/include/grid/tria.h b/deal.II/deal.II/include/grid/tria.h index f51f9844ed..af3e4c9e7d 100644 --- a/deal.II/deal.II/include/grid/tria.h +++ b/deal.II/deal.II/include/grid/tria.h @@ -1132,6 +1132,97 @@ class TriaDimensionInfo<2> { * vertex with the same number of the old quad. * * + * \subsection{Implementational conventions for three spatial dimensions} + * + * By convention, we will use the following numbering for vertices, lines and + * faces of hexehedra in three space dimensions. Before giving these + * conventions we declare the following sketch to be the standard way of + * drawing 3d pictures of hexhedra: + * \begin{verbatim} + * *-------* *-------* + * /| | / /| + * / | | / / | + * / | | / / | + * * | | *-------* | + * | *-------* | | * + * | / / | | / + * | / / | | / + * |/ / | |/ + * *-------* *-------* + * \end{verbatim} + * The left part of the picture shows the left, bottom and back face of the + * cube, while the right one shall be the top, right and front face. You may + * recover the whole cube by moving the two parts together into one. + * + * \subsubsection{Vertices} + * + * The vertices on the front face are numbered exactly the same way as are + * the vertices on a quadrilateral. The vertices on the back face are numbered + * similarly by moving the front face to the back (no turning, no twisting, + * just a shift): + * \begin{verbatim} + * 7-------6 7-------6 + * /| | / /| + * / | | / / | + * / | | / / | + * 3 | | 3-------2 | + * | 4-------5 | | 5 + * | / / | | / + * | / / | | / + * |/ / | |/ + * 0-------1 0-------1 + * \end{verbatim} + * + * \subsubsection{Lines} + * + * Here, the same holds as for the vertices: the lines of the front face are + * numbered as for the quadrilateral, for the back face they are just shifted. + * Finally, the four lines connecting front and back face are numbered: + * \begin{verbatim} + * *---6---* *-------* + * /| | / /| + * 11 | 5 11 10 | + * / 7 | / / | + * * | | *---2---* | + * | *---4---* | | * + * | / / | 1 / + * 3 8 9 3 | 9 + * |/ / | |/ + * *---0---* *---0---* + * \end{verbatim} + * The direction of the front and back lines is as for the respective faces, while + * the connecting faces always point to the back: + * \begin{verbatim} + * *--->---* *--->---* + * /| | / /| + * ^ | ^ ^ ^ ^ + * / ^ | / / | + * * | | *--->---* | + * | *--->---* | | * + * | / / | ^ / + * ^ ^ ^ ^ | ^ + * |/ / | |/ + * *--->---* *--->---* + * \end{verbatim} + * + * \subsubsection{Faces} + * + * The faces are numbered in the same order as the lines were numbered: front + * face, back face, then the four side faces: + * \begin{verbatim} + * *-------* *-------* + * /| | / /| + * / | 2 | / 5 / | + * / | | / / | + * * | | *-------* | + * | 6 *-------* | | 4 * + * | / / | | / + * | / 3 / | 1 | / + * |/ / | |/ + * *-------* *-------* + * \end{verbatim} + * + * * \subsection{Warning} * * It seems impossible to preserve #const#ness of a triangulation through -- 2.39.5