19.2 The OVF 1.0 format

19.2.1 Segment Header block

The Segment Header block start is marked by the line “# Begin: Header” and the end by “# End: Header”. Everything between these lines should be either comments or one of the following file descriptor lines. They are order independent. All are required unless otherwise stated. Numeric values are floating point values unless “integer” is explicitly stated.

  • title: Long filename or title.

  • desc: Description line. Optional. Use as many as desired. Description lines may be displayed by post-processing programs, unlike comment lines which are ignored by all automated processing.

  • meshunit: Fundamental mesh spatial unit, treated as a label. The comment marker ‘##’ is not allowed in this label. Example value: “nm”.

  • valueunit: Fundamental field value unit, treated as a label. The comment marker ‘##’ is not allowed in this label. Example: “kA/m.”

  • valuemultiplier: Values in the data block are multiplied by this to get true values in units of “valueunit.” This simplifies the use of normalized values.

  • xmin, ymin, zmin, xmax, ymax, zmax: Six separate lines, specifying the bounding box for the mesh, in units of “meshunit.” This may be used by display programs to limit the display area, and may be used for drawing a boundary frame if “boundary” is not specified.

  • boundary: List of (x,y,z) triples specifying the vertices of a boundary frame. Optional.

  • ValueRangeMaxMag, ValueRangeMinMag: The maximum and minimum field magnitudes in the data block, in the same units and scale as used in the data block. These are for optional use as hints by postprocessing programs; for example, mmDisp will not display any vector with magnitude smaller than ValueRangeMinMag. If both ValueRangeMinMag and ValueRangeMaxMag are zero, then the values should be ignored.

  • meshtype: Grid structure; should be either “rectangular” or “irregular.” Irregular grid files should specify “pointcount” in the header; rectangular grid files should specify instead “xbase, ybase, zbase,” “xstepsize, ystepsize, zstepsize,” and “xnodes, ynodes, znodes.”

  • pointcount: Number of data sample points/locations, i.e., nodes (integer). For irregular grids only.

  • xbase, ybase, zbase: Three separate lines, denoting the position of the first point in the data section, in units of “meshunit.” For rectangular grids only.

  • xstepsize, ystepsize, zstepsize: Three separate lines, specifying the distance between adjacent grid points, in units of “meshunit.” Required for rectangular grids, but may be specified as a display hint for irregular grids.

  • xnodes, ynodes, znodes: Three separate lines, specifying the number of nodes along each axis (integers). For rectangular grids only.