Is there any way to see a spotlight's light beam in Unity? A bit like if you used a flashlight in a foggy area?
The easiest way to simulate this would be to have a mesh for your light cone, and render that using, for example, the additive particle shader.
check out this system, it has support for cone casting so you can set the parameters to fit your spot light. It ‘fakes’ volumetric light by smart placement of images planes with a custom shader. Don’t know this is what you meant by visible beam? One of the pics has a projector basically doing the same thing.
system link: