How to make the ground moisture change effect of blocking rainwater like Cyberpunk 2077

Hi there !

I am trying to make an effect of the ground moisture change caused by the rain being blocked, as shown in the picture below.

I have tried to use the scene catcher to shoot depth textures in the negative Z-axis direction and apply them to the decal material, but it is not very good because of the limited texture resolution. Here is the screenshot.

Then I tried the runtime virtual texture and applied it to the ground material. It was easy to use, but the edges were too sharp to make the humidity looks natural and I didn’t know how to blur it. Here is a screenshot.

Is there any way to achieve this humidity change effect ?