unity3d - How to replicate the following animal crossing effect in unity?

Question

Idea/Requirement: So I was thinking of spawning characters behind a door/arch way that is visible to the camera and wanted them to fade in as they walked through the door/arch way.

First Impressions: It looks like its a depth based shader on a single quad. Any help or tips in the right direction would be super helpful

It can be seen clearly from 10:12 - 10:16 in the following video

question from:https://stackoverflow.com/questions/66067077/how-to-replicate-the-following-animal-crossing-effect-in-unity

Answer 1

Waitting for answers