Gridgen Version 13.3.9 - October 2000

Gridgen Version 13.3.9 features a major improvement to the tetrahedral mesher in the Block, Run Solver Unstructured command. The improved tet mesher is faster, extremely less likely to have to modify the boundary mesh, and much more robust. The GUI for interacting with the tet mesher has changed so please consult Section 11. Also, a new environment variable is necessary for establishing the directory into which it should write some temporary files. It is described in Section 3.3.

SPR 13.0457

Corrected a tabulation error in the IGES import summary printed to the shell window.

SPR 13.0498

Changed the manner in which memory is allocated for importing large geometry models from IGES files that allows much larger files to be imported without running out of memory.

SPR 13.0503

Joining two undimensioned connectors no longer inserts a break point at the original join location.

SPR 13.0543

Fixed a minor problem with the color of nodes. Nodes were sometimes a different color (green) than the connectors that use them (cyan) due to the display color not being copied correctly to cloned nodes.

SPR 13.0560

Two problems fixed here. First, an error was fixed in database entity status checking that caused most entities to be disabled after creating domains using On DB Ents. Second, an error in the application of the Max Dev clustering constraint for connectors and unstructured domains (in the Defaults menu) that resulted in much smaller triangles being generated than necessary has been fixed.

SPR 13.0302

Failure of the tet mesher with use of the Decay attribute has been eliminated.

SPR 13.0303

The tet mesher is significantly more boundary preserving with the result that prism layers can now easily be attached to tets.

SPR 13.0304

Removed the tet mesher's sensitivity to interfaces to pyramid cells.

SPR 13.0314

Memory management problems in the tet mesher have been eliminated.

SPR 13.0334

More memory management improvements in the tet mesher.

SPR 13.0368

When creating unstructured domains on database surfaces using the On DB Ents command, if tri meshing fails due to periodicity of the underlying database surface Gridgen will revert to a second meshing pass using a 3D meshing algorithm with projection.

SPR 13.0491

Fixed a problem in splitting a structured block that was imported from a PLOT3D file in which their are singularities (collapsed edges) and the split location is at the singularity.

SPR 13.0506

Creating a subdomain would disable display of the domain so that creating a second subdomain on the same domain was difficult. Also, after projecting a subdomain only the subdomain is drawn making it difficult to determine the success of the projection. Both of these have been fixed.

SPR 13.0509

Improvements were made to the structured block splitter in order to handle splitting of overset blocks that aligned exactly with adjacent grids in the overlap region.

SPR 13.0514

Fixed a synchronization problem with periodic connectors to ensure that the modified connector is updated first before the periodicity is applied.

SPR 13.0519

Fixed yet another problem in structured block splitting that would cause the i,j,k coordinate alignment routine to align in a direction other than the join direction.

SPR 13.0525

A problem was fixed in which it was impossible to recreate a face in an existing structured block. Instead the block had to be recreated from scratch.

SPR 13.0546

A major collision between the used of shared variables between the connector modification and extrusion commands has been fixed. This would result in the extrusion boundary condition inexplicably changing type while setting other extrusion attributes.

SPR 13.0549

At the request of AeroSoft, the GUST export filter now writes an FV-UNS file. When combined with Gridgen's generic boundary condition file sufficient data is available for running GUST.

SPR 13.0551

Fixed a problem with the Examine command's hiliter that artificially limited its traversal across structured domains.

SPR 13.0555

When only planes existed in the database you could still create On DB Ents connectors - with disastrous results. Planes are now eliminated as candidate entities for connector creation.

SPR 13.0556

A typographical error in the code would result in serious problems if a Gridgen file containing references to a database was imported when exactly zero database entities had previously been imported. This now works correctly, including warnings, etc.

SPR 13.0558

The domain duplicate checking algorithm would miss domains created between blocks during extrusion. This has been fixed.

SPR 13.0562

Major improvements have been made to Gridgen's tetrahedral mesher that make it more robust (less likely to fail and less likely to modify boundary triangles) and faster. The two most notable differences in its operation now are new environment variables and a single attribute to control its operation: an upper limit on memory usage.

The new environment variables required for operation of the tet mesher (both of which are set automatically by the run script) are:

GRIDGEN_BINDIR

The environment variable GRIDGEN_BINDIR is the path name of the directory in which the executable program for Gridgen's tetrahedral mesher (called gridgen_tet ) is found. This directory is normally the same directory in which the Gridgen executable is found. If you've installed the tet mesher's executable program in /usr/local/bin then, using the C-shell, you should set the environment variable this way:

setenv GRIDGEN_BINDIR /usr/local/bin

See Section 11 for more information on the tetrahedral mesher.

GRIDGEN_TEMPDIR

The environment variable GRIDGEN_TEMPDIR is the path name of the directory into which Gridgen will write temporary data files for communication with the tetrahedral mesher. If GRIDGEN_TEMPDIR is not set, Gridgen will write the temporary tet meshing files into the directory from which Gridgen was run. For example, if you'd prefer that Gridgen write its temporary data files to /usr/tmp then, using the C-shell, you should set the environment variable this way:

setenv GRIDGEN_TEMPDIR /usr/tmp

See Section 11 for more information on the tetrahedral mesher.

SPR 13.0565

Default spacing constraints and distribution function are now applied to new connectors even if they're undimensioned.

SPR 13.0566

Exporting a Gridgen file containing blocks created by extrusion would print error messages to the shell window about cleaning up bad data. This overly-verbose and actually harmless error message has been removed since it was inadvertently printed in the first place.

SPR 13.0570

The quality of the graphical display of cells on a cutting plane drawn in solid + wireframe mode in the Examine command has been improved.

SPR 13.0571

An error in the connector duplicate checking routine would cause failure when using the Connector, Modify, Redimension command to apply a new Average Spacing to all connectors in the grid.

SPR 13.0573

When creating domains or blocks by extrusion and when running N steps and when simply pressing return at the prompt to get the last used (default) number of steps, Gridgen would hang on Windows platforms. This has been fixed.

SPR 13.0577

Added extra code to the connector merging routines to make sure that locked unstructured domains are updated properly when the connector merge results in a dimension change.

SPR 13.0581

Bitmap (.bmp) files are now included as a screen dump option in the Display menu.

SPR 13.0582

Fixed an error in the special command for automatically completing a domain during create by assembling edges that would result in a failure on Windows or HP-UX.

SPR 13.0583

Fixed a problem with Domain Create's Auto Next Edge feature that would forget whether a structured or unstructured domain was being created.

SPR 13.0584

It was possible to get the File Browser on Windows platforms to get stuck if you didn't have permission for any of the folders in the current folder. Now Gridgen will display a list of all mapped drives in cases like this.