2011

The key points when using volumetric lighting are:
■ Remember to turn the Scattering parameter of light sources on if you want to see their volumetric effects.
■ Use Medium Density and Medium Color to define brightness and color of the lit medium.
■ Use a solid color shader set as density shader for simulation of density variations in the medium.
■ Decrease the Error Bound parameter, if image appears spotty outside shadow areas.
■ Increase the Min LOD parameter, if areas with volumetric shadows appear spotty.
■ For fast previews, set the Error Bound parameter high, and the Min LOD parameter small.
■ For best results, set the Fall Off option to Inverse Square Law, and turn on Auto Exposure.
Image-based Lighting
Image-based lighting is where an image is used to light a scene. In the real world, every object is lit not only by
light sources like the sun, lamps, and so on, but also by everything around. Standing in the middle of a street,
a person will be lit by the sun, the blue sky, the brown buildings and the grey street. Emulating this form of
lighting clearly has the potential to create incredibly realistic images.
Images used in this lighting method are a special kind of image, called a High Dynamic Range Image or HDRI.
This type of image has the capability of lighting a scene with incredible accuracy. In the Presenter window, an
HDRI is wrapped around the scene as a sphere, and color and brightness from the HDRI are cast onto the 3D
model to light it.
A model lit with normal lights
The same model lit with image-based lighting
You can see the difference this form of lighting can make to rendered images. And the enormous advantage here
is that it is much easier to set up than traditional lighting.
Advanced Lighting | 367