MegaCads Release Notes

MegaCads

Release Notes

Version 2.1

Release date: 14 April 1997

This is the official release of the MegaCads system. MegaCads stands for Multiblock elliptic grid generation and Computer aided design system.

VERY IMPORTANT !
VERY IMPORTANT !

The number of possible children of a process has been increased from 99 to 999 in MegaCads 2.1. Due to this extension old script files (SAVE_PROC_FILE) have to be translated because the indices will change. If all processes uses variables no changes are necessary. But otherwise MegaEdits "Auto Name" function has to be used to translate all indices into variables (Important: use the old MegaEdit version). Proceed in the following way:

make a copy of the script for savety reasons
make sure that all implicit defined process names are used in all following processes (Variables-Browser-Apply)
translate remaining processes with "Auto-Name" from the MegaEdit Edit menu
if sub scripts are in use make sure that variable names do not exist twice in the main and sub script (e.g. change the variable names in the sub script from P_.. to S_..)

New version

The main feature of MegaCads-2.1 is the new GUI which has been defined together with DASA Bremen (Dr. H. Schwarten and D. John). The dialog windows of the old version have been replaced by buttons. These buttons can be found in a 5#4 array of buttons. Due to this the usable drawing area has been increased and redrawing of a scene forced by moving dialog windows is eliminated. Because more than 20 functions are available they are grouped together (CAD, Grid). If another menue is selected or the Arrow button is pushed the buttons change their function. Below the buttons the function for the definition of the working surface can be found. the three buttons to the right are not active in MegaCads-2.1.

Next is a command line which shows text like "Sel Entity" or "O.k. ready to execute". Necessary inputs (parameter, options) can be handled with the 2#4 buttons below and the four text input fields. The "EXE" and the "Undo" button are valid for all functions. All other buttons (Modify, ..., Block, Edge, those from the topology menue) are not active in MegaCads-2.1.

The entity list and the graphic functions are also integrated into the MegaCads main window. Now a "dynamic" graphic mode is available which allows that objects follow directly the mouse during translation, rotation or zoom. The mode can also be turned on using F9. When the dynamic mode is active no selection of entities is possible !

Standard views are available. If MegaCads has been compiled using Mesa (OPENGL-XTERM in MegaConfigure) or OpenGL (OPENGL-CONSOLE in MegaConfigure) six clipping planes can be used.

Details about the functions can be found in the help texts. Use the right mouse button to get the help for a function.

The most important new features are:

GUI/Graphics:

new GUI
dynamic viewing mode using VOGL, Mesa or OpenGL
clipping planes (Mesa, OpenGL only)
selection of default views
reduction of core dumps when something went wrong during the selection process
stop the selection process during concatenation of splines or grids by a clic into deep space of the drawing area
pixmaps are available as pictures and text

CAD/Grid:

biharmonic surface grid generation (needs four first layers)
2D-offset function
improved surface/surface intersection
improved projection
object description in the status line (optional, see News.txt)
allowed number of child processes increased (from 99 to 999)
3d biharmonic smoothing: user gets hint to which side of a start grid a first layer belongs
debugging

MegaEdit:

automatic update of the sty-file
all MegaCads functions can now be handled by MegaEdit

MegaHelp:

update of the help texts

See also News.txt

We hope that we have delivered a version with a minimum of bugs. Currently, we cannot test all possible cases, so core dumps might happen from time to time. If something like that happens check the script file and remove wrong process data and try to start MegaCads again. If you are working on a bigger project save the entity file every hour (file/dump/save entities). Please let us know what went wrong and we are going to try to fix the problem for a future version. Some already known bugs which cuold not be fixed for 2.1 are:

if MegaCads stops with XbaeMatrix: No columnWidths specified the reason might be :
- the name of the MegaCads executable is different than the name in MegaCads.rsc
- the resources are not loaded (or loaded using the wrong DISPLAY variable
wrong selection or pushing of "EXE" or another function button before all data is collected may cause wrong data in the script file or may cause a core dump (it should work in most cases)
3d biharmonic smoothing is very parameter sensitiv (trail-and-error)
this is also true for the surface grid generation
Surface/surface intersection does not work correctly for all cases
projection of grids, splines may fail
installtion of Mesa might be not straight forward

The MegaCads development is still in progress (see MEGAFLOW schedule). Currently we are working on:

the integration of an advanced suface/surface intersection (Dr. H. Schwarten, DASA)
the integration of an advanced elliptic smoothing technique (Dr. P. Niederdrenk, DLR GO)
the acceleration of th elliptic smoothing using multigrid (L. Xue, TU-Berlin)
the integration of a basic GTM
an advanced graphic functionality
a function to convert Euler into Navier-Stokes grids
the 3d offset function

Requirements in Hardware and Software

The current release of MegaCads is supported on the following platforms:

Silicon Graphics systems running IRIX 5.3 or above
DEC AXP systems running OSF/1 2.0 240 or above
HP PA-RISC systems running HP-UX
IBM RISC systems 6000, running AIX
Linux (no official support from the MegaFlow/MegaCads team but you can contact Ing.Office O. Brodersen, Nordstr. 40, 38106 Braunschweig for support)

All systems must have a flavour of Unix and the Motif toolkit libraries installed. For an improved graphic visualisation OpenGL 1.1 is necessary. Otherwise developers if your hardware platform is not in the list, but fulfills the above requirements.

Documentation

The main part of the documentation is supplied as html-files. It should be read using the online help application MegaHelp, which comes with your copy of MegaCads. These documents can also be read and imported by World Wide Web browsers as well as many text processing programs. If you prefer a printed manual, you can use MegaHelp to create paper copies of single documents. MegaHelp supports ASCII and Postscript (TM Adobe Inc.) printers.

Operation

MegaCads is using the widgets of the Motif toolkit to offer an attractive user interface. This means an optical pleaseant appearance as well as an intuitive, easy to learn user interface. If a working installation has already been installed on your system, you just have to make sure that the environment variables are set and that the resource file has been read into your X-window server (see configuring MegaCads).
To set the environment variables and to load the resource file (MegaCads.rsc) into your X-window system, you can execute the C-shell script environment, which is located in the TOOLSdirectory of your local MegaCads installation.
If you want to do some real work, you should create a new project directory where MegaCads will store all intermediate files and results. Now you are ready to type mcads at the Unix command prompt.

Directory structure

The tar file that comes with your edition of MegaCads, contains files in various subdirectories, which will be expanded into the tree structure shown below:

Figure 1: MegaCads directory tree structure

Tools

This release of MegaCads includes the tools and applications listed below. All the binaries will be located in a subtree of the BINARIES directory of the local system. The C-shell scripts will be located in the TOOLS directory of the local installation. There is no need to copy any of these files manually; the MegaConfigure script will do all the necessary steps for you. The alias names are defined in the MegaEnvironment script.

MegaCads alias mcads: the binary of the main program
MegaEdit alias medit: the binary of the script editor
MegaUpdate alias mup: a C-shell script that updates you older script files to the current standard,
MegaEnvironment: a C-shell script that sets up your working environment. This script should be executed each time you want to use the MegaCads system. Therefore it should be added to your .cshrc file (include a source MegaEnvironment line in your .cshrc file).
MegaConfigure alias mcf: a C-shell script that configures your personal MegaCads setup. You should execute this script once if you have never used this release of MegaCads.