It is a cross-media era now. A new kind of animation creation thinking which combines the interactivity of computer games with the narrative and appreciation of animation. It is interactive animation. The emergence of interactive animation greatly shortens the developer's development cycle, and more importantly, enhances the interactive and immersive experience of players watching movies. This creation is to study the 3D animation created by real-time rendering with a game engine, and it use a non-linear narrative method for animation screenwriting. The story mainly describes that the protagonist will choose whether to rescue people in distress, at the same time it would combine the interaction with the viewer to express reflection on the current social situation. In terms of expression techniques, this creation uses the real-time rendering technology of the game engine to explore the interactivity of animation and a reasonably optimized creation process. In terms of the content of the work, this creation is an interactive animation creation that discusses the study of altruistic behavior.