Ray Sensor for Switch light

Question

I research in Smart Home Project, belongs to Blender Game Engine. But, I don't understand in Blender Game Engine for switch the light part, why do we need the "ray sensor"? What does ray sensor do for? Could someone help me explain this?

Answer 1

It can be used to detect objects within a specified range (and given material or property) along one axis. Check out the docs:
https://docs.blender.org/manual/en/latest/game_engine/logic/sensors/types/ray.html