Making the raster image is a two step process. First you must make the output file suitable for the image processing program, and then execute the program using the new file as input to produce the raster output. The problem is that each of the programs write a different output file format, which will probably have to be converted to something more appropriate for you. It is impossible to predict what that might be, so we'll say how to convert the different file types to RGB and let you use the tools listed in Table 8.1 to get what you need. Raster3D produces an RGB file, so you don't need to do anything. POV and POV3 produce TARGA files, which can be converted on SGI machines with the program /usr/sbin/fromtarga. Rayshade creates RLE image files, which can be converted on SGI machines with /usr/sbin/fromutah. Radiance generates an .oct file, which can be converted with the rview and rpict commands in the Radiance distribution.
The free program display from ImageMagick - see
should be able to read and interconvert all of these formats.
We suggest using either Raster3D or Radiance as they are the fastest of the programs. The first is the easiest to understand and the second has many, many options (different types of lights, textures, ...).
The image processing program input formats are straight text so they are easy to modify. This is most often done to create a larger raster file, though some have other global options which you may wish to change. For instance, by default the Raster3D file turns shadows on. We suggest you consult the relevant documentation to determine what can be modified in the file.
To actually render the current image into an output file, first set up the graphics in VMD just as you wish the output to appear. Then, either use the Render form, or the following text command, to create the input file and start the rendering program going: