Creator is an environment for creating interactive simulations.
Let s consider what an ideal environment for creating simulations would be like, and then see how Creator modifies this idealized environment to produce a truly practical implementation. Suppose the user wants to create a simulation where a character walks to the right and jumps over fences. In an ideal PBD environment, the user would create this program by telling the environment to watch what I do and then dragging the character to the right and over the fences as shown in the figure. Creating an appropriate program from this input requires a considerable amount of inferencing. It is not clear whether the ground is relevant, whether this is a single action or a series of actions, and what the program should do when other characters are present on the screen.