How does photography retouch realize people swimming in a cup?

About this question, someone answered it in the past, and answered it, and I answered it, sharing how to use snapseed to put swimming characters in cups. This paper mainly uses the double exposure tool in snapseed and the view modification

tools to realize the masking function and map the button. Below are two material maps, which can be used by friends to practice. The synthetic effect is at the end of the article, and the bottom of the slip can be seen!

material 1 (don't ask what's in the cup, I don't know, it's not Xiang anyway? )

Material II

Open snapseed software, import the cup material, click the Tools button, and open the double exposure

Open the double exposure, then import a swimming material picture, and click the red circle to import.

reduce the opacity, adjust the size to coincide with the base map, and then increase the opacity to the maximum, so that the figure map can be clearly displayed. At this time, the base map cup will turn completely black, regardless of the mask behind it.

Click on the upper right corner circle to view the modified content and bring up the mask.

Click on the brush tool software to jump to the original base map style, and it will be displayed just by smearing characters in the cup. Adjust the parameters between 1_ carefully. The renderings are as follows. Is it simple and interesting? I like to help you with a compliment before I go!