Soft Particles (Soft Particles) is a technical term that is extremely important in rendering and optimizing game graphics (technical art). A rendering technology that uses the difference in depth values to smoothly fade out the boundary line where translucent particles collide with opaque objects such as the ground or walls, eliminating unnatural edges.
An example from the real world: A natural phenomenon in which the steam in a bath melts gently at the boundary where it intersects with the "hot water surface and wall"
Soft particles are a natural fading phenomenon in which the steam rising from the bathtub blends seamlessly and disappears at the moment it hits the bathroom wall.'' Without this technology, the part where the steam (polygon plate) sinks into the wall would appear as a sharp straight line, as if drawn with a ruler. By automatically blurring the boundaries by saying, ``They're close to each other, so let's make them a little thinner,'' you can make them blend incredibly naturally into the 3D space.
Illustration: Soft Particles (Infographic that illustrates the basic processing flow and mechanism of soft particles) in Japanese in an easy-to-understand manner
Detailed mechanism and operating principle
Get the ground depth from "Camera Opaque Texture" in Shader Graph, compare it with the current pixel depth, and implement a soft process that smoothly approaches 0 in the opacity (Alpha) of the nearby parts.