DX Tips

• In all the documentation, the directory "/usr/lpp/dx" should be replaced by "/usr/local/lpp/dx".
• When all the licenses are used up, DX doesn't tell you that there are no more licenses available, instead it gives a strange error message:

  Starting DX user interface
  This invocation of Data Explorer does not allow editor access (-edit).
  Try image mode (-image), or forcing a developer license (-license develop).
  

  You can type dx -license develop to get more information, such as:

  Starting DX user interface
  Unrecognized license
  Data Explorer could not get the requested license
  IBM Visualization Data Explorer: status 0 (OS)
  
  The current users of this product are:
  User       Node                      Using    Start Time       
  schaudt    i7.msi.umn.edu            1        Tue Jul 30 16:18:07 1996
  

• I usually don't send an image to the printer, instead I save it as a PostScript image, or as a TIFF image. A TIFF image needs to be converted to PostScript or SGI's rgb format to print.
• Often jagged Lines appear when an image is printed. There are several procedures to follow to improve the quality of lines. No procedure seems to work for everything. Please contact Barry Schaudt (schaudt@msi.umn.edu) for assistance. One option is using hardware rendering, and setting an attribute on lines to antialias the lines when rendering them. Hardware rendering will cause the entire image to be different: sometimes it is better, sometimes worse. Another option is to render at high resolution, and then reduce the size of the image. Again, contact Barry Schaudt for assistance.
• The image quality can be significantly better when the image depth is set to 24 bits. Here are two images,
  
  The image on the left was rendered at a depth of 24 bits and captured using snapshot, the one on the right was rendered at 24 bits (This means the image on the left appeared on the screen), and then saved from the file menu of the image module, a distinct loss of quality.

  In general, I find that when using an image depth of 24 bits, snapshot works somewhat better than saving the image from the file menu of the image module or saving the image from the render module. Note: there are many good reasons to do so: such as you can control the image size and you can mechanize the process to save a sequence of images.

• When creating isosurfaces, insufficient memory can be a problem - This is true of all isosurface algorithms. . There are ways to tune the memory usage of a dx program and ways to reduce the size of the data set. Contact Barry Schaudt for assistance.