Shading Tips for advanced users

In large productions, making materials HDAs has several advantages.

It is possible to change the material HDA and have all .hip files automatically pick up the changes.
It is possible to swap materials by adjusting the HOUDINI_OTL_PATH.

Note

Using material overrides largely breaks this work-flow since the overrides cannot be changed outside the .hip file.

Default Object Properties

Houdini is initially set up to assume that mantra is the primary renderer. If your studio uses a different primary renderer, it may be more useful to have a different set of initial object properties.

The creation script adds properties to the object using the opproperty command when an object is added. You can change this creation script. The opproperty command uses the parameter lists defined in $HH/soho/parameters. Since all of these files are searched using the default Houdini path and support include files, it is possible to customize the initial set of properties.

For example, to customize which parameters are defined on a geometry object, you might create $HOME/houdini9.0/soho/parameters/IFDmantra9.0.user.ds which has contents that look like the following:

//
// Included when defining mantra parameters
//

#define USER_DEFINED_IFD_GEOMETRY_PARMS

parm {
    name        default_geometry
    label       "Default Geometry"
    parmtag     { spare_category        "__spare_parmlist" }
    parmtag     { spare_parmlist        "categories lightcategories reflectcategories"  }
}

This will change the default object to only have three rendering properties: categories, lightcategories and reflectcategories.

Other renderers can be customized in a similar fashion.