The Ambient Occlusion shader is also capable of reflective occlusion. When reflective occlusion is activated, the shader changes the sampling pattern in order to distribute samples around the direction of reflection, rather than the direction of the surface normal (or bent surface normal). This is most useful for adding detail to environment-only reflections created using environment maps.
You can create reflection occlusion for individual objects, but it is easiest to do it a the render pass level, as shown in the following example, where an environment map shader has been added to the current pass’ shader stack:
For more information about environment maps, see Using Environment Map Shaders [Texturing]. For more information about pass-level shaders, see Applying Shaders to Partitions [Rendering].
To apply scene-wide reflective occlusion via a render pass
Before you start: this procedure assumes that the scene contains reflective objects whose surface shaders (or other reflection shaders) have their Reflection Mode parameter should be set to Environment only
For more information about reflectivity, see Reflectivity [Material and Shader Basics]. For more information about environment maps, see Using Environment Map Shaders [Texturing].
1. Open an explorer (press 8) and press p to set the scope to passes.
2. Select the pass in which you want to create the reflective occlusion effect and press 7 to open the render tree.
3. From the render tree’s Nodes menu, get the following shaders:
- Environment > Environment
- Illumination > Ambient Occlusion
4. Connect the Ambient Occlusion shader to the Material node’s Environment Shader Stack port.
5. Connect the Environment node to the Ambient Occlusion shader’s Bright Color port.
6. Edit the Environment node’s properties to choose the image you wish to use as an environment map.
7. Edit the Ambient Occlusion node’s properties and make sure to set the following:
- Turn the Reflective parameter on.
- Reduce the Spread value to sharpen the occlusion in the object’s reflective surface.
8. Continue to tune the ambient occlusion parameters as needed. See Setting the Ambient Occlusion Shader Options for details.
To apply reflective occlusion to an object
Before you start: this procedure assumes that the object in question is reflective, meaning that it has a surface shader, or other reflection shader controlling its reflectivity. Furthermore, the surface shader’s Reflection Mode parameter should be set to Environment only.
For more information about reflectivity, see Reflectivity [Material and Shader Basics]. For more information about environment maps, see Using Environment Map Shaders [Texturing].
1. Select the object for which you want to create the reflective occlusion effect and press 7 to open the render tree.
2. From the render tree’s Nodes menu, get the following shaders:
- Environment > Environment
- Illumination > Ambient Occlusion
3. Connect the Ambient Occlusion shader to the Material node’s Environment port.
4. Connect the Environment node to the Ambient Occlusion shader’s Bright Color port.
5. Edit the Environment node’s properties to choose the image you wish to use as an environment map.
6. Edit the Ambient Occlusion node’s properties and make sure to set the following:
- Turn the Reflective parameter on.
- Reduce the Spread value to sharpen the occlusion in the object’s reflective surface.
7. Continue to tune the ambient occlusion parameters as needed. See Setting the Ambient Occlusion Shader Options for details.
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