2009

Table Of Contents
To turn on the caustics preset settings
1 In the Render Settings window, select the Quality tab and set the Quality
presets setting to PreviewCaustics.
This turns on the presets that control the quality of the caustics.
2 Close the Render Settings window.
Mental ray for Maya uses photons to simulate the caustic effects in a scene.
Photons are small packets of energy emitted from a light source into the scene.
The photons travel throughout the scene, refracting through transparent
objects or reflecting off reflective surfaces. The renderer keeps track of the
illumination that results from this photon emission in a file called a photon
map. The overall caustic simulation is determined from the photon calculations
that result.
In addition to having the spotlight emit light into the scene you set the light
to also emit caustic photons. The overall caustic effect is determined from the
photon calculations that result.
To turn on the caustics lighting settings
1 In the Hypershade, double-click on the icon for spotLightShape1.
2 In the Attribute Editor, click the spotLightShape1 tab to display the
lighting attributes for the spotlight.
3 Open the mental ray section, and in the Caustic and Global Illumination
attributes set:
Emit Photons: On
Photon Intensity: 8000
466 | Chapter 9 Rendering