How can I add volumetric lighting to a spotlight?

Questions & Answers
1

I'm using the free edition of Unity.

Basically, I want to have the beams of light coming out of my lights be visible, because they're an integral part of the gameplay, so the player needs to see the airspace covered by the light. This is a 2D game, by the way. Is there some transparent material I can use to get the light to show up in blank airspace?

As you can see in the example below, the light is visible in thin air.

EDIT: Example.

4

My first thought would be an image effect, but pro only so that idea doesn't work.

My next idea would be to create a mesh in the shape of a funnel that protrudes out from you light. It isn't the most performance efficient, but you could do this relatively cheaply. Then write a shader that makes the object mostly transparent, then blur the edges some.

Even if you cannot write custom shaders (they're really not that valuable in Unity unless you need a special effect. The built-in ones do a fantastic job in most cases.), then you could get a close result using a standard transparent shader.

http://answers.unity3d.com/questions/1574/visible-light-beams

http://forum.unity3d.com/threads/37986-Post-Process-Godrays-In-Unity?highlight=visible+light+rays

http://forum.unity3d.com/threads/62398-Powerful-Low-Draw-Call-Volume-Light-amp-Light-Effect-Solutions?highlight=visible+light

http://forum.unity3d.com/threads/27713-volumetric-light-fog?highlight=volumetric+light

http://forum.unity3d.com/threads/2660-How-to-create-a-light-cone-or-shaft-of-light?highlight=volumetric+light

For the most part, the threads all say post-processing or use a mesh-either a cone or a bill boarded plane- to do volumetric lighting.

2

I'm not quite sure what you are asking but you can have a 'Halo' on your light which allows you to see the light source.

Click on your light, then in the Inspector check halo.

3

I'm not sure if you ve tried using a spot light but if it did't get the effects you wanted...

1) You can try using a line renderer.

OR

2) A more expensive method would be using a particle emitter to shoot light beams. You'll have to shape your materials will to get a good effect but I'll still recommend the line renderer method for the more functional effect.

5

For Unity free, there is this system (also works on pro) Unity Asset Store - The Best Assets for Game Making

It generates light shafts on planes with a texture, they collide dynamically (can be turned of) and can sample real-time color from textures (like church windows). It can give really realistic and good looking results. Maybe this is something you where looking for? Since most meshes with transparency can look odd.