You can use the scene objects’ Visibility Property Editor [Properties Reference] to precisely control how each object participates in final gathering calculations. Every object has the following three final gathering visibility parameters:
• Caster: specifies whether or not an object casts final gathering rays into the scene.
• Visible to Sampling: specifies whether the object is visible to final gathering rays cast by other objects. Turning this option off causes final gathering rays to pass through the object.
Turning this option off makes the Sampled option unavailable, since an object that is not visible to sampling rays cannot be sampled.
• Sampled: specifies whether an object’s surface is actually sampled by final gathering rays cast by other objects. Turning this option off causes the object to absorb final gathering rays.
The scene shown here was rendered using exaggerated final gathering values to make the final gathering effect very prominent.
The character is standing in a corner between a red wall and a green wall. The floor is grey.
Notice how the colors of the various objects bleed into one another. This gives a good indication of how each object’s final gathering rays are sampling.
Turning off the character’s Final Gathering > Caster parameter causes it to stop casting final gathering rays to sample the scene. As a result, none of the surrounding colors bleed onto the character.
Notice that the walls are still casting final gathering rays, so the character’s color bleeds onto them.
Turning off the character’s Final Gathering > Visible in Sampling parameter makes it invisible to sampling rays cast by other objects. The rays simply pass through the character. The result is that the walls and floor sample one another, but do not sample the character.
Notice that the character is once again a caster, and is sampling the walls, whose color is bleeding onto it.
Turning off the character’s Final Gathering > Sampled parameter causes it not to be sampled by other objects’ final gathering rays. Instead of letting the rays through, it absorbs them.
As a result, the walls and floor are not able to sample one another where the character occludes their final gathering rays.
Notice that although the character’s color does not bleed onto the walls, a pattern of occlusion is visible where it block final gathering rays.
The options give you fine control over a scene’s final gathering computations. For example, you might want to limit the final gathering to specific objects, or remove only a few objects from the final gathering computations. By default, all of these options are turned on.
To set an object’s final gathering visibility options
1. Select the object whose final gathering visibility options you wish to adjust, and open an explorer (press 8).
2. Expand the object’s hierarchy and click its Visibility node to open the object’s Visibility property editor.
3. On the Rendering tab, toggle Caster, Visible to Sampling, and/or Sampled options as needed.
Adjusting Final Gathering Visibility Options for Grouped Objects
If your scene contains a lot of objects, final gathering visibility options can be difficult to manage on a per-object basis. In complex scenes, it’s easier to group objects and use overrides to control final gathering visibility options for all of the objects in a group. For example, you might use this technique to prevent all of a scene’s background objects from casting, or being sampled by final gathering rays.
