9.4.2 POS ASCII file format

The POS ASCII file is Gmsh's old native pot-processing format, now superseded by the format described in MSH ASCII file format. It is defined as follows:

$PostFormat
1.4 file-type data-size
$EndPostFormat
$View
view-name nb-time-steps
nb-scalar-points nb-vector-points nb-tensor-points
nb-scalar-lines nb-vector-lines nb-tensor-lines
nb-scalar-triangles nb-vector-triangles nb-tensor-triangles
nb-scalar-quadrangles nb-vector-quadrangles nb-tensor-quadrangles
nb-scalar-tetrahedra nb-vector-tetrahedra nb-tensor-tetrahedra
nb-scalar-hexahedra nb-vector-hexahedra nb-tensor-hexahedra
nb-scalar-prisms nb-vector-prisms nb-tensor-prisms
nb-scalar-pyramids nb-vector-pyramids nb-tensor-pyramids
nb-scalar-lines2 nb-vector-lines2 nb-tensor-lines2
nb-scalar-triangles2 nb-vector-triangles2 nb-tensor-triangles2
nb-scalar-quadrangles2 nb-vector-quadrangles2 nb-tensor-quadrangles2
nb-scalar-tetrahedra2 nb-vector-tetrahedra2 nb-tensor-tetrahedra2
nb-scalar-hexahedra2 nb-vector-hexahedra2 nb-tensor-hexahedra2
nb-scalar-prisms2 nb-vector-prisms2 nb-tensor-prisms2
nb-scalar-pyramids2 nb-vector-pyramids2 nb-tensor-pyramids2
nb-text2d nb-text2d-chars nb-text3d nb-text3d-chars
time-step-values
< scalar-point-value > … < vector-point-value > … 
    < tensor-point-value > …
< scalar-line-value > … < vector-line-value > … 
    < tensor-line-value > …
< scalar-triangle-value > … < vector-triangle-value > …
    < tensor-triangle-value > …
< scalar-quadrangle-value > … < vector-quadrangle-value > …
    < tensor-quadrangle-value > …
< scalar-tetrahedron-value > … < vector-tetrahedron-value > …
    < tensor-tetrahedron-value > …
< scalar-hexahedron-value > … < vector-hexahedron-value > …
    < tensor-hexahedron-value > …
< scalar-prism-value > … < vector-prism-value > …
    < tensor-prism-value > …
< scalar-pyramid-value > … < vector-pyramid-value > …
    < tensor-pyramid-value > …
< scalar-line2-value > … < vector-line2-value > …
    < tensor-line2-value > …
< scalar-triangle2-value > … < vector-triangle2-value > …
    < tensor-triangle2-value > …
< scalar-quadrangle2-value > … < vector-quadrangle2-value > …
    < tensor-quadrangle2-value > …
< scalar-tetrahedron2-value > … < vector-tetrahedron2-value > …
    < tensor-tetrahedron2-value > …
< scalar-hexahedron2-value > … < vector-hexahedron2-value > …
    < tensor-hexahedron2-value > …
< scalar-prism2-value > … < vector-prism2-value > …
    < tensor-prism2-value > …
< scalar-pyramid2-value > … < vector-pyramid2-value > …
    < tensor-pyramid2-value > …
< text2d > … < text2d-chars > …
< text3d > … < text3d-chars > …
$EndView

where

file-type

is an integer equal to 0 in the ASCII file format.

data-size

is an integer equal to the size of the floating point numbers used in the file (usually, data-size = sizeof(double)).

view-name

is a string containing the name of the view (max. 256 characters).

nb-time-steps

is an integer giving the number of time steps in the view.

nb-scalar-points

nb-vector-points

…

are integers giving the number of scalar points, vector points, …, in the view.

nb-text2d

nb-text3d

are integers giving the number of 2D and 3D text strings in the view.

nb-text2d-chars

nb-text3d-chars

are integers giving the total number of characters in the 2D and 3D strings.

time-step-values

is a list of nb-time-steps double precision numbers giving the value of the time (or any other variable) for which an evolution was saved.

scalar-point-value

vector-point-value

…

are lists of double precision numbers giving the node coordinates and the values associated with the nodes of the nb-scalar-points scalar points, nb-vector-points vector points, …, for each of the time-step-values.

For example, vector-triangle-value is defined as:

coord1-node1 coord1-node2 coord1-node3 coord2-node1 coord2-node2 coord2-node3 coord3-node1 coord3-node2 coord3-node3 comp1-node1-time1 comp2-node1-time1 comp3-node1-time1 comp1-node2-time1 comp2-node2-time1 comp3-node2-time1 comp1-node3-time1 comp2-node3-time1 comp3-node3-time1 comp1-node1-time2 comp2-node1-time2 comp3-node1-time2 comp1-node2-time2 comp2-node2-time2 comp3-node2-time2 comp1-node3-time2 comp2-node3-time2 comp3-node3-time2 …

The ordering of the nodes is given in Node ordering. For second order elements, the first order nodes are given first, followed by the nodes associated with the edges, followed by the nodes associated with the quadrangular faces (if any), followed by the nodes associated with the volume (if any). The ordering of these additional nodes follows the ordering of the edges and quadrangular faces given in Node ordering.

text2d

is a list of 4 double precision numbers:

coord1 coord2 style index

where coord1 and coord2 give the X-Y position of the 2D string in screen coordinates (measured from the top-left corner of the window) and where index gives the starting index of the string in text2d-chars. If coord1 (respectively coord2) is negative, the position is measured from the right (respectively bottom) edge of the window. If coord1 (respectively coord2) is larger than 99999, the string is centered horizontally (respectively vertically). If style is equal to zero, the text is aligned bottom-left and displayed using the default font and size. Otherwise, style is converted into an integer whose eight lower bits give the font size, whose eight next bits select the font (the index corresponds to the position in the font menu in the GUI), and whose eight next bits define the text alignment (0=bottom-left, 1=bottom-center, 2=bottom-right, 3=top-left, 4=top-center, 5=top-right, 6=center-left, 7=center-center, 8=center-right).

text2d-chars

is a list of nb-text2d-chars characters. Substrings are separated with the null `\0' character.

text3d

is a list of 5 double precision numbers

coord1 coord2 coord3 style index

where coord1, coord2 and coord3 give the XYZ coordinates of the string in model (real world) coordinates, index gives the starting index of the string in text3d-chars, and style has the same meaning as in text2d.

text3d-chars

is a list of nb-text3d-chars chars. Substrings are separated with the null `\0' character.