Overview
The Shadows group of attributes controls two distinct aspects:
- Specifies what objects are casting shadows, wether these shadows are created using shadow maps or ray tracing.
- Specifies if the render engine should do a pre-pass to generate shadow maps that may be needed for rendering the main image (or layers of images).
The Shadows group
Shadow Linking
Specifies the method to determine the objects that are shadowed by lights. It affects all types of shadows: depth map, deep maps and ray traced. The available options are:
| Option | Description |
|---|---|
| Use Light Links | Objects will cast shadows from the lights that are considered illuminating the objects by the light linker. This is the default. |
| Use Shadow Links _______________________ | Objects will cast shadows from the lights that are considered shadowing the objects by the light linker. This allows distinct object-light relations for illumination and shadowing. |
| Ignore Light & Shadow Links | All visible objects will cast shadows from all lights. |
Auto-Generate Shadow Maps
Controls wether shadow maps should be automatically generated or not. The default value is on.
Opacity Threshold
Only objects with opacities greater than or equal to the Opacity Threshold will appear in shadow maps. The default value is [0.0, 0.0, 0.0], which means that all objects will be included in the shadow map, even completely transparent ones. If this value is set to [1.0, 1.0, 1.0], only completely opaque objects will be rendered into shadow maps. Note that this parameter is only useful for depth shadow maps as deep shadow maps correctly handle semi-opaque surfaces. For users familiar with the RenderMan standard, this is the equivalent of the following RiOption:
Option "limits" "zthreshold" [r g b]