Upgrades to QMG 1.1 and incompatibilities

• QMG 1.1 can generate surface meshes as well as area and volume meshes. See the mesh generation documentation.
• QMG 1.1 supports some simplified data formats. See the documentation on external interfaces.
• The source code has been rewritten in a cleaner object-oriented fashion.
• The quadtree/octree mesh generation algorithms have been redesigned for better efficiency and memory use. For instance, mesh generation results for test case test5 running on a Sun Sparcstation are in the following table. The same size upper bound (0.4) was used. Note that QMG1.1 improves on QMG1.0 in all measures of performance. (This table uses the nonstandard "table" HTML extension so your browser may have trouble with it.)
  

  Version	Running time	Worst aspect ratio	Number of tets
  QMG 1.0	20 min	1122	20167
  QMG 1.1	3.5 min	270	11540

  
  
• QMG 1.1 now runs under the Microsoft Windows NT operating system as well as Unix. See the installation instructions.
• QMG 1.1 now allows Tcl/Tk as a scripting language, as well as Matlab.
• QMG now renders its 3D graphics in VRML format. See the gmviz and gmplot documentation.

• Breps and their faces may now be infinite. Faces of breps are now tagged with points inside the brep to allow the handling of infinite breps.
• Internal boundaries of a face can be of any face of lower dimension.
• Tolerances on geometric routines were formerly predefined constants, but in QMG1.1 they are exposed to the user in all routines where they occur.
• The API has been expanded with many new routines. See the reference manual.

• Size functions are handled somewhat differently in QMG1.1. However, any size function for QMG1.0 written in Matlab or Tcl should also work in QMG1.1.
• The Ascii format in QMG1.1 is not compatible with the Ascii format in QMG1.0. However, there is a conversion routine to read a brep or simplicial complex in QMG1.0 format.
• Simplices in QMG1.1 are now oriented. If you read in a non-oriented simplicial complex (for instance, a simplicial complex generated by QMG1.0), then you should turn off the "checko" option to gmchecktri.
• The set boolean operators behave differently. A major difference is that the cleanup of internal boundaries no longer takes place automatically and must be done with a call to gmbrepsimplify. There are subtle differences in the way intersections involving degeneracies are processed.
• Colors are handled differently in QMG1.1. Colors are now 4-tuples of numbers, with the fourth entry standing for opacity.
• Some routines, such as gmmeshgen, have new calling sequences.
• The unix standalone routines have a different calling sequence because of the changes to the mesh generator.
• The routine gmpolygon now returns polygons inscribed in the unit circle rather than polygons circumscribing it.
• Matlab QMG now uses environment variables QMG_ROOT and QMG_DATA in conjunction with startup.m to set its path. In QMG 1.0 the path was set using the environment variable MATLABPATH.

This documentation is written by Stephen A. Vavasis and is copyright (c) 1996 by Cornell University. Permission to reproduce this documentation is granted provided this notice remains attached. There is no warranty of any kind on this software or its documentation. See the accompanying file 'Copyright' for a full statement of the copyright.

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