Volumetric light is a beautiful effect you can add to Unity to enhance the realism of lighting.
Real light reflects from air particles to cast glowing cones between the source and the surfaces of objects.
Unity doesn’t have this built in yet, but there are several packages that can help you add it.
SlightlyMad Volumetric Light by Michael Skalsky
Michael Skalsky aka SlightlyMad has made a beautiful and free open source volumetric light package that looks great.
Brackeys has a great tutorial video on how to use SlightlyMad’s open source package.
Hx Volumetric Light by Lexie Dostal
The commercial-grade VR supported volumetric light package also supports transparency and numerous other cutting edge features.
Hx Volumetric Lighting is the easiest way to get high quality volumetric lighting in your Unity scene, adding depth and realism with rays of light and fog of variable density. It’s easy to use and runs efficiently. VR Single pass stereo is now supported (5.4.1+).
• Supports Shadow casting lights
• Supports multiple lights – any number and combination of point lights, spot lights, and directional lights.
• It’s dynamic – you can move lights around in real-time.
• Vary the air density with particle emitters or 3D noise.
• Use height fog to get a low hanging fog look.
• Mie scattering for more realistic results
• Supports transparency.
• Supports light cookies.
• Supports low resolution rendering with advanced up-sampling and temporal sampling, allowing faster framerates.
• Easy to use. Just drop a few scripts on your camera and lights.
• Forward/deferred render Path.
• Directx 9/OpenGL3 and above.
• VR Supported with single pass stereo Enabled (Unity 5.4.1+)
• Shader Model 3 and above.
• Desktop and console support.(mobile is not supported)
• Custom transparency shaders will need to be modified