Hi everyone，
I’d lilke to implement a searchlight in game, need to see “light beam” just like small dust in the air.
and the “light beam” can be rotated like other gameobject.
I tried “Spotlight” and “Halo” but no luck, any tips?
you can’t do it in unity , it does not support volumetric light .
In attempt to try and fake the effect, you could also try attaching a particle emitter object, with a highly opaque dust texture, as a child of the light with the same forward velocity as the light. It isn’t the best way, but could possibly work to simulate the desired effect.
Sure Unity does ‘support’ volumetric light - just look at the light shafts in the Bootcamp demo. 
But in this case you need a slightly different effect. There are some advanced cg techniques that would allow you to approximate the integral of the lit dust particles in the beam, but that would probably be an overkill in your situation.
If I were you I would go for the good old semi-transparent, self-illuminated cone, maybe even if slightly smokey texture scrolling over it in world space (not object space!). Totally doable in Unity as well, of course.
thanks for the info. that’s very helpful! 