Creating an image is generally about telling a story. In a single frame, like the painters of the past, we can describe a situation, a hero in danger, the triumph of good versus evil, and so on. The element that gives the most immediate sense of where we are is the environment. There are many different models that are available in the marketplace. We can use sci-fi environments, medieval castles, a modern metropolis, or an exotic garden. The possibilities are infinite and in addition to what is available, we can easily mix elements from one set to the other. For example, we could take a medieval tower and place it in the middle of a spaceport. Surely, we can come up with a good reason for that to happen!
The point in this is that we have no limits because unlike physical models, we can move things around with just a few clicks of the mouse. Keep that in mind and let your imagination run wild.
So, the environment is generally the element that determines the mood of the...