A mixed reality system including a display and camera is configured to receive video of a physical scene from the camera and construct a 3D model of the physical scene based on the video. Spatial sensing provides pose (position and orientation) updates corresponding to a physical pose of the display. First user inputs allow a user to define an input path. The input path may be displayed as a graphic path or line. The input path is mapped to a 3D path in the 3D model. Second user inputs define animation features in association with the 3D path. Animation features include an object (e.g., a character), animation commands, etc. The animation commands may be manually mapped to points on the 3D path and executed during an animation of the object guided by the 3D path.