How to highlight only the affected area of ​​the shape?

Question

Unity

There is a sonar that emits a signal in the form of a plane with a collider.
When colliding with an object, only the area of ​​the object that was touched by the signal is painted over.

How to highlight/select a shaded area?

Answer 1

The collider will not help here - it does not give out data on the "hit area". You need to look towards Projector and custom shaders.