As previously explained and discussed that the towel magic trick uses masking and this is pretty much time consuming and as well be accurate with timing and syncing the two shots, one is with the person in the shot and the other is just the same location with no camera moves and the camera must be on tripod or static not to move. Any tiny move and displace will effect the situation and will make the shot look very fake, and as well other bits that are important like lighting and the shadow and the feather option of the to mask to blend in with the original footage. It definitely sharp eyes and planning to accurately and easily manipulate the the shots while using mask.
Step by step
1. Need to generate to video of the same position
2. Shoot the first video with the person dropping the towel
3. Then shot another video with the no on in the frame – so basically this will be used to mask over it.
4. Create to layers and manipulate it – sync it accordingly
5. Use mask option to mask the first layer and make sure the mask moves when the towel drops.
The result of the video