Trick++: Mixed-reality illusion

The illusion I created relied on apparent motion using video. Originally, I applied the technique known as stop motion on a decorative object. Two pieces of tape were put in a cross pattern on a desk to mark the location for the object to be set. With the object positioned on the desk, I took a picture of the scene. Next, I very slightly turned the object clockwise, making sure that it retained its place on the tape, and took another picture. This process of rotating the object incrementally and snapping a picture was repeated until one complete revolution was made. In total, 71 images were taken. A program called 3DRT took these input images and created a GIF file that cycled through them at a rapid rate; this rate was so high that we perceive the succession of images as continuous motion. An online converter changed the GIF file into an MP4 file, which is shown below.

 

To improve this trick, I sought a means to shed doubt on the implementation of stop motion. My inclination was to insert a second object into the scene and have it appear to move due to gravity. After all, had I resorted to stop motion alone to capture these two movements, I would have needed to take a burst of shots for each position of the rotating object on the desk, and then match each appropriate rotating/falling pair to assemble the video frames; this would be an exceedingly laborious process. I accomplished the introduction of a second object, as a dark orange ball, digitally with the aid of a program called Blender. Using Blender, I imported my MP4 file of the rotating object, created an orange sphere, put the MP4 file and sphere on a timeline, and inserted a series of LocRotScale keyframes while changing the timeline marker and sphere position between subsequent keyframes. I used an Alpha Under blend for the MP4 file and an Alpha Over blend for the sphere. In order to provide a convincing visual appearance of the two objects merged together in the scene, I had the table act as an interaction platform. That is, the ball fell from a high height and appeared to make contact with the table, after which it bounced back to a lesser height before falling once more. A video of the resulting blended scene is shown below.