Each descriptive file specifies all of the information inherent to that object, i.e. everything about it that is independent of its position. For example, if we were rendering a red box flying through space, then the scene file would contain the fact that it was a box along with its path through space. The box's descriptive file would contain the box's size and the fact that it was red.
In the case of some of the more complex objects, the descriptive files may sometimes specify additional files, extending the hierarchy another level. For example, a ripple on the ocean's surface would be listed in the ocean's descriptive file and then have its own descriptive file.
For the example input files discussed, some parameters are not actively discussed, and should generally not be changed. More advanced or adventuresome users can change some of those parameters once they have a thorough understanding of their use. Discussions of these cases are designated by the symbol
Entries in all RenderWorld files are separated by either spaces or tabs. The exact number of spaces or tabs doesn't matter.