Maya 2012 Tutorial
How to Add Volumetric Lights in Maya
The Volumetric Lighting is used to simulate light passing through fog or smoke. This effect is often used in theater by adding dry ice to the stage. You can also see this type of effect with street lights on a foggy pier.
This type of lighting works with Point, Spot and Volume lights
Another example of this type of lighting can be found in the topic, Adding Smoke to Light.
Add a text object to the scene by choosing Create > Text.
Add a spot light by choosing Create > Lights > Spot Light.
In the Orthographic views (Top, Front and Side), use the Move (w key) and Rotation (e key) tools to position the light so it illuminates the back of the text object.
Position the Perspective view camera so you are looking at the front of the text object.
Select the light and open the Attribute Editor.
Set the Cone Angle to 90 and open the Light Effects section.
Click the checkerbox next to Light Fog and change the fog color by clicking the Color rectangle. Click the Fast Drop Off checkbox.
Click the checkerbox next to the Density slider, then click the Cloud texture in the 3D Textures section.
Return to the main light tab and open the Shadows section. Click the Use Depth Map Shadows checkbox.
Render your image by clicking the Render Current Frame icon. If the effect is too subtle, increase the Fog Intensity slider in the main light tab, Light Effects section. Adding a low intensity light to the front of the object helps highlight the letter details.