Technical Notes

  "RenderSoft VRML Editor was used to create this file." That's the comment the program inserts into every file it writes. The RenderSoft is a good starting point, but in fact is incapable of writing some of these operations.
  Since the RenderSoft VRML (Virtual Reality Modeling Language) Editor doesn't allow you to see the code as it's being written, I've been using that program in concert with Netscape 3.0 and a Notepad, in order to observe the effects of changes in the file, and to write it with greater mathematical precision. After getting a working image in RenderSoft, I save and load the V1.0 .wrl file into Netscape and Notepad. Then, making changes in the file (but not too many at once) in Notepad, I save the changes and refresh the browser, to observe the effects. I'm also finding the VRML Specification to be helpful on certain technical points, though it's a huge document, and for the most part over my head.
  To save you the trouble I went through, let me point out that the directional lights enclosed in grouping nodes derive their direction from the translations of the geometries (spheres, cylinders, etc.). Regarding the vector quantities, the resultants of the translations on the x and z axes represent the planets' respective distances from the Sun, times 10^-7. The translations on the y axis are arbitrary within limits prescribed by the inclination of a given planet's orbit to the ecliptic.
  Now, since we're being technical here, you might ask why I didn't use the inverse square law to determine the intensity of the lighting. Well, I did, sort of, but doing that alone rendered the reflected light virtually undetectable, except from the surface of Mercury. Instead, I compressed the range of values arbitrarily to match the range of distances within the solar system. For a given planet, I first divided the distance from the Sun in miles by 10¹⁰, then added 1. This was the figure entered as the distance in the calculation. Not terribly scientific, I know, but honestly, I did try to come up with a better formula; I just don't have the mathematical wherewithall.
  So, for example, in determining the light intensity for the Earth, I first determined the distance in miles divided by 10¹⁰ (.0093), added 1, and squared it, giving 1.0186865. Dividing 1 by this product gives a quotient rounded off to .982, which is inserted into the .wrl file as the value for the intensity of the light directed at the Earth.
  You'll observe that the Earth's equator is inclined 23.45 degrees to the ecliptic. In the file this is achieved by rotating the sphere (not the texture) 0.409 radians.
  The rings of Saturn were challenging; in the end I used a transparent disc wrapped in a .gif image, the central portion of which is transparent. I certainly hope it works with your vrml plug-in or browser! They do seem to vary widely in their performance, particularly with regard to their image rendering capabilities.