Solaris

Pattern Matching Prims in Solaris

Houdini Documentation

Reference LOP

Reference LOP is used for combining a main stage with a specific prim from another stage. Think of it as copy and pasting a folder in a specific directory into another folder.

Additional Render Vars LOP

Used for creating custom AOVs based on primvars and other attributes. The same functionality is contained within the Karma Render Properties LOP but does not exist in the universal Render Properties LOP, which necessitates the use of this node.

usda.usd

/

Chair

chair_geo chair_mtl

material1

usdb.usd

/

mtl

blue pink

Using a Reference LOP and setting the Primitive Path to /Chair/chair_mtl and the Reference Primitive Path to /mtl/ will merge all of mtl’s children primitives onto chair_mtl creating the following:

/

Chair

chair_geo chair_mtl

material1 blue pink

Restructure Scene Graph LOP

Reparent Primitives
Rename Primitives
Remove Primitives

Prune LOP

Used for making primitives invisible or deactivated
Invisible means that other primitives in your scene can still interface with the invisible prim, for example, for constraints
Inactive essentially suspends the prim and it is unable to be affected by any operations until you reactivate it

Configure Primitive LOP

Used for changing basically every USD property of a prim
Most importantly, you use this node to change the active/visibility state of a prim

Store Parameter Values LOP

Workaround by Houdini to create and store temporary values
Creates a prim at /HoudiniLayerInfo with the attributes
This prim is not saved out when saving out the USD with USD ROP

You can access the attribute in an expression with a helper function in loputils or you can access it manually using Python.

import loputils
this_node = hou.pwd()
input_node = this_node.inputs()[0]
val = loputils.fetchParameterValues(input_node,"yourValue")
 
return str(val)

Accessing Usd Prims with Python