Gmsh Mesh File Format
=====================
The 'msh' file format is the native output file format for
Gmsh. The file is divided in two sections (enclosed in $KEY and
$ENDKEY pairs): $NOD/$ENDNOD defines the nodes and $ELM/$ENDELM
defines the elements.
$NOD
number-of-nodes
node-number x-coord y-coord z-coord
...
$ENDNOD
$ELM
number-of-elements
elm-number elm-type elm-region unused number-of-nodes node-numbers
...
$ENDELM
All the syntactic variables stand for integers except x-coord,
y-coord and z-coord which stand for floating point values. The
elm-type value defines the geometrical type for the element:
1 Line (2 nodes, 1 edge).
2 Triangle (3 nodes, 3 edges).
3 Quadrangle (4 nodes, 4 edges).
4 Tetrahedron (4 nodes, 6 edges, 4 facets).
5 Hexahedron (8 nodes, 12 edges, 6 facets).
6 Prism (6 nodes, 9 edges, 5 facets).
7 Pyramid (5 nodes, 8 edges, 5 facets).
15 Point (1 node).
The elm-region value is the number of the physical entity to which
the element belongs.
Parsed View Format
==================
View "name" {
type of element (list of coordinates) {list of values} ;
...
}
12 base objects can be displayed:
type of element list of coordinates list of values
--------------------------------------------------------------------------------
scalar point SP 3 1 * nb time steps
vector point VP 3 3 * nb time steps
tensor point TP 3 9 * nb time steps
scalar line SL 6 2 * nb time steps
vector line VL 6 6 * nb time steps
tensor line TL 6 18 * nb time steps
scalar triangle ST 9 3 * nb time steps
vector triangle VT 9 9 * nb time steps
tensor triangle TT 9 27 * nb time steps
scalar tetrahedron SS 12 4 * nb time steps
vector tetrahedron VS 12 12 * nb time steps
tensor tetrahedron TS 12 36 * nb time steps
The coordinates are given "by node", that is (x,y,z) for a point, (x1,y1,z1,x2,y2,z2)
for a line, (x1,y1,z1,x2,y2,z2,x3,y3,z3) for a triangle, ...
The values are given by timestep, by node and by component. That is, for a vector line,
{valxnode1time1,valynode1time1,valznode1time1, valxnode2time1,valynode2time1,valznode2time1,
valxnode1time2,valynode1time2,valznode1time2, valxnode2time2,valynode2time2,valznode2time2, ...}
Ascii View Format
=================
Binary View Format
==================
int one=1;
fprintf(file, "$View /* %s */\n", name);
fprintf(file, "%s %g\n", name, version);
fprintf(file, "$EndView\n");
fwrite(&One, sizeof(int), 1, PostStream);