Machinima is the art of using someone else's rendering engine to portray a story different from the original intent. Machinima is the practice of live-action filmmaking within a 3D virtual space. However, do to accessibility, it mostly defaults to existing game engines and their associated IP. This will change as more sandbox-theme virtual 3D space is developed.
Moe Napoli writes: Just learned over at the Thinking Machinima blog, that Microsoft has released "content usage rules" that allow the end user to create machinima with a certain set of their titles, including the Halo franchise and ShadowRun (but also Age of Empires!). This is a fairly large step into the allowance of user-generated content, but the rules are extremely limiting — the terms keep people from creating anything that extends the property's universe. Question is, isn't that the reason people make machinima in the first place?