Global Illumination

Global Illumination

Maya 2012 Tutorial


How to Add Global Illumination with Maya Mental Ray



Global Illumination occurs around us every day. Whenever light strikes an object, the light changes color and bounces on to the next object. The new object is then lit with color from the previous object.

To see this in action, stand in front of the red wall on a bright sunny day. The sun strikes the red wall and anything the light bounces to turns red.

To accomplish this in Maya we must first activate Photons for the light and then turn on Global Illumination in the Render Settings.


Step One

Follow the steps in the topic, Adding Mental Ray Textures. You should have a sphere, floor and area light in your scene.

Step Two

Select the light and in the Attribute Editor, Caustic and Global Illumination section, click Emit Photons.

Step Three

Open the Render Settings panel by clicking the Render Settings icon.

Step Four

Click the Indirect Lighting tab and open the Global Illumination section.

Step Five

Click the Global Illumination checkbox.

Step Six

Render your current scene and notice that the red from the floor projects onto the sphere.

Step Seven

If the Global Illumination is too intense, decrease the light's Photon Intensity setting in the Attribute Editor.

Photon Options

In the light's Caustic and Global Illumination section you can alter the Photon settings. The Photon Intensity value is similar to the standard light intensity slider.

Global Illum Photons controls the actual number of Photons released by the light.

Global Illumination Options

In the Render Settings, Indirect Lighting tab, Global Illumination section, you have access to Accuracy, Scale, Radius an Merge Distance settings.

Can't Find Mental Ray?

If Mental Ray doesn't appear in the Render Settings, Render Using: menu, choose Window > Settings/Preferences > Plug-in Manager. Make sure Mayatomr.bundle is loaded. career skills