| Previous Topic | Next Topic | Contents | Features |
The ETCH plot may not indicate the location of a geometry error as readily as a COLOR plot, and at times may be confusing. The error messages in errfile.txt, however, are the same as when ray tracing with COLOR. In some cases, the appearance of a cell boundary where none was expected points to the error. Errors which give fuzzy boundaries in COLOR plots will yield the same result with ETCH plots.
Since geometry checking follows rays through the entire model, it requires more computer time than without checking. The computer time can be reduced by lowering the color resolution or decreasing the size of the graphics window or subwindow, but the completeness of the geometry test is also diminished. A model defined in surface geometry usually requires more time to check than the equivalent model in a body description.
To use the Etch test option, check the Test item in the Options menu or type TEST ON and then Etch. The usual requirements for ray tracing must be met-a finite spatial window and at least one cell must be nontransparent.