Plasmas

In most virtual worlds, the only significant plasma is fire. Fires are usually treated as individual objects, but not always entirely realistically. It’s easy enough to model them to emit virtual heat and light, but the problem is that in real life fires spread. In virtual worlds, they don’t. You can set fire to combustible materials and they’ll burn; they may even ignite nearby objects. However, they won’t usually spread to the environment.

There are two reasons for this. The defining one is that it’s very hard to do! Fires are transforming events: If you drop a lit match in dry grasslands, you transform it into a charred landscape; trees are replaced by blackened stumps, buildings are empty shells, and everywhere is bereft of life. Predicting the collapse of structures when arbitrary parts of them burn away is very difficult.

The second reason is that even if out-of-control fires could be modeled, it would be unwise to have them. Half of all real-world property fires are due to arson, and the temptation to destroy a virtual world that way would be irresistible. Even players who weren’t crazed vandals might try it out just the once. “Gee, do you think I’d get experience points for killing 200 bears if I set fire to the woods?”