The archive file hlp.zip contains the files:
|hlp.f90||the source code|
|drh.cmn||you will need it to compile hlp|
|input.txt||instructions for preparing input & interpreting output|
|arc12721.txt||the original program description from COSMIC|
|Sample cases for this program are:|
|wbf.wgs||simple sample case with vertical fin|
|tnd7505.wgs||wing-body configuration of NASA TN D-7505|
|tnd4211.wgs||wing-body configuration of NASA TN D-4211|
|ex1.wgs,ex2.wgs,ex3.wgs,ex4.wgs||examples from the LaWgs document TM 85767|
|auxiliary viewing programs|
|dpr.xls||Viewing program (from Dan Raymer) (alternate to gnuplot)|
|danplot.exe||2008 version of dpr.xls (also from Dan Raymer) (Thanks, Dan)|
To compile this program for your machine, use the command
gfortran hlp.f90 -o hlp.exe
Linux and Macintosh users may prefer to omit the .exe on the file name.
Launch the program by typing hlp.exe at the command line. The program will ask you for the name of the input data file. This must be a file written to conform to the Langley Wire-Frame Geometry Standard. Next, the program asks for three viewing angles, which correspond to yaw, roll, and pitch. Enter values in degrees. To complete the viewing definition, you need to specify the distance of the eye from the object. Unless you are looking for an extreme perspective effect, give a number that is large compared to the dimensions of the object. The image will still be adjusted to fill the screen.
After calculating the scene, the program produces a file called hlp.gnu that defines the vectors in 2-D that describe the object. Each line in hlp.plt defines a point (x,y). Whenever there is a blank line in the file, this means that the line to the next point is invisible (from the old days of pen plotters, this is called a pen-up draw). This file may be displayed directly with gnuplot with the command
gnuplot> plot 'hlp.plt' with lines
You will need to use the command
gnuplot> set size ratio -1
to insure that you have a square viewport on your screen to match the square window of the output from hlp.
There is another file called hlp.ps that is produced by this program. This is the same picture, but encoded in PostScript format.
If you do not have gnuplot or a PostScript interpreter installed on your system, there is yet another way to visualize the output. Try out the Excel program called dpr.xls (for Dan Raymer, who wrote the program). This requires you to have Microsoft Excel on your system, though. Dan wrote a new version that will work even if you do not have Excel.
It is best if you compile the programs using your Fortran compiler with the appropriate options for your computer system. If you are unable or do not wish to do this, you may download hlpexecs.zip containing the files hlp.exe, hlp.mac, and hlp.lnx, the executable programs for Windows, Mac OS X, and Linux, each compiled generically for an Intel CPU.