Some users were unsure of how to use the SSS Compounds because there was no explanation of how to generate lightmaps for these fast subsurface scattering effects. To add insult to injury, the SimpleSSS and SkinSSS shader compounds were pointing the wrong help topics. This has all been fixed:
• See Fast Subsurface Scattering Shader Compounds and Generating Lightmaps for the SSS Compounds [Lights and Cameras].
• See SkinSSS Shader Compound and SimpleSSS Shader Compound [Shader Reference].
Copying and Pasting Nodes in the Render Tree
The Copy Shader Branch command that is available by right-clicking a shader node in the render tree is no longer supported. As a result, the procedure for copying and pasting shader nodes has been updated in the user guide to the following:
You can copy and paste nodes within the same render tree or to another render tree. The only node that you cannot copy and paste in this way is the Material node.
To copy and paste shader nodes in the render tree
1. In the render tree, select one or more nodes that you want to copy.
- Use the Ctrl key or rectangle-select in the render tree to select multiple nodes.
- Middle-click a node to branch-select it: every node leading up to it is also selected.
2. Press Ctrl+C. Only the selected nodes are copied.
3. In the same object’s render tree or another object’s render tree, click an empty region to make sure that no nodes are selected.
4. To paste the selected node(s) into the render tree workspace, right-click an empty area of the render tree workspace and choose Paste or press Ctrl+V.
Instance Shape Node versus Set Instance Geometry Compound
Information has been added to the user guide about using the Instance Shape node instead of the Set Instance Geometry compound for instance geometry that is not animated. This node provides the simplest and fastest way to create large numbers of instances whose geometry is not animated.
The Instance Shape node is actually used inside the Set Instance Geometry compound, but does not include certain parameters that the compound provides for using animated instance geometry. These parameters are unnecessary for unanimated instance geometry and actually increase their evaluation time, especially noticeable when you’re using a large number of instanced objects.
As well, the Set Instance Geometry compound uses the ShapeInstanceTime attribute which implements the instances using stand-ins (assemblies) when rendering with mental ray. The stand-ins write the instanced geometry to disk and then load it for rendering. As a result, this may cause memory problems while rendering many, many animated particle instances (see mi Archives and Stand-Ins [ Rendering ] for more information).
Bottom line: If the instance geometry is not animated, use the Instance Shape node.
See ICE Particle Instances (Objects as Particle Shapes) [ ICE ] for more information.
Getting and Setting Particle Attributes
A section about using particle attributes in the ICE tree has been added to the ICE user guide. This section describes the different ways in which you can get and set particle attributes.
As well, many particle attributes are now discussed in the user guide according to their context, such as the Collision attributes being discussed in ICE Rigid Bodies [ ICE ].
See Using ICE Particle Attributes [ ICE ] for more information.
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