When you use a file-based loader to load grid data, Tecplot RS reads recurrent variables on demand. When you choose a new time step for display, Tecplot RS will retrieve the data from the file.
To retrieve the data efficiently, Tecplot RS uses a “map” to the start of each time step in the file, which it creates when reading the entire file the first time you open the file.
The data ranges of each variable also serve as important pieces of information. To automatically set up the legend for contour values, it is necessary to know the minimum and maximum values for each variable over all time steps.
The very first time you use a restart file (which contains the time-dependent data), Tecplot RS reads the entire file to find all the time steps and compute all the ranges. It then saves these data in a small file called an Index File. The file has the same root name as the grid file, but with an extension of .rsrst.
If Tecplot RS detects that this file does not exist, or if the Restart file has a newer date than the index file, Tecplot RS will create an index file automatically. The initial load will take longer because Tecplot RS scans the entire file.
Once an up-to-date index file exists, you can load a grid with load-on-demand much faster.
You can also create both the index and the .rsgrid files with the RSPreprocess.exe utility (included in your installation). You can launch this utility automatically at the end of a simulator run. See Section J - 1 “RSPreprocess” for more information.