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Contents 1 Rendering Parameters / Rendering Properties 1.1 What is it? 2 How to add them 3 Hierarchical Nature of Rendering Parameters

Rendering Parameters / Rendering Properties

What is it?

Sometimes called "properties", Houdini has a hierarchical system of parameters in place where you can choose from a list of parameters for the various renderers and add them to your nodes. These parameters can be set various values to instruct the particular renderers to do certain things. A shader assignment is a good example of a Rendering Parameter.

These parameters are really just preset SpareParameters (with special meaning to SOHO and the Viewport) that you can add and remove from nodes at will.

How to add them

The ParameterPane has a little gear icon. In this menu there is an "Edit Rendering Parameters..." item. This will invoke a dialog with the available rendering parameters available. You can drag n drop, RMB-"Install" or select than click the arrow button in the middle of the pane to add a parameter to your node. You can remove them from the node using this dialog too. You can also just RMB on a rendering parameter and select "More > Delete Spare Parameter".

This is the pane where you can add/modify/delete Rendering Parameters (and other SpareParameters)

Hierarchical Nature of Rendering Parameters

You can use many of these parameters in a heirarchical way. Consider this order:

1. The ROP you're rendering from,
2. The Camera specified in this ROP
3. The Object you're rendering
4. The Object's GeometryAttributes, in order:
   1. Detail/Global
   2. Primitive
   3. Point
   4. Vertex

So, by example, if you add a Surface Shader (shop_surfacepath) property of blue plastic to the ROP, all objects in the scene will be rendered with that shader. However any assignments of the shop_surfacepath at the deeper level will override the ROP assignment. So, you can add a shop_surfacepath property to, say, your Object and override it just for that object. The same is true for geometry-level assignments.