Maya Rendering Guides

Volumetric Lighting

How do you create an effect such as a flashlight beam shining through fog? This lighting effect is called volumetric lighting, and you can use it to create some stunning results, which can sometimes be time consuming to render.

You cannot apply volumetric effects to Ambient and Directional light types. To add a volumetric effect to any of the other types of lights, select the light, and in the Attribute Editor under the Light Effects section, click the checkered Map button to the right of the Light Fog attribute. This will create a new render node that will appear in the Hypershade and Multilister windows. Once you click the Map button, the Attribute Editor will take you to the lightFog node.

The way Maya handles volumetric lights is to attach a lightFog node to the light. The Color and Density attributes under this node control the brightness, thickness, and color of the fog attached to that light. Furthermore, in the light's Attribute Editor, you can control the fog with the Fog Spread and Fog Intensity settings. Fog Intensity increases the brightness of the fog, and Fog Spread controls how well the fog is defined within its confines. For example, a Spot light with a fog will show the fog in its cone. Figure 10.39 shows how spread affects the conical fog shape.

Figure 10.39 Fog Spread affects how the fog dissipates to the edges of the cone.

To remove a fog effect, right-click the Light Fog label in the light's Attribute Editor and choose Break Connection from the shortcut menu.

Figure 10.40 Light glow and lens flare turned on for the back light

If you want the light fog-cast shadows to make rays of light within the fog, simply check Use Depth Map Shadows for the light. You will have to increase the depth map Resolution for a higher-quality image.