Houdini USD Plugins

Houdini USD Plugins


Configure Environment

There are a couple of prerequisites to using the Houdini plugins.

  • Ensure that you built the Houdini plugins, this is enabled in the build with -DPXR_BUILD_HOUDINI_PLUGIN passed as an option to cmake. 
  • Ensure that the following environment variables are configured. We'll refer to the install location of your USD build with USD_INSTALL_ROOT, this is determined in the build with the cmake flag, -DCMAKE_INSTALL_PREFIX.
     
Name Meaning Value

HOUDINI_PATH

This is the search path the Houdini uses to find resources.

USD_INSTALL_ROOT/third_party/houdini:&

HOUDINI_DSO_ERROR

Setting this to 1 helps debug issues with loading plugins into Houdini. 1

HOUDINI_DSO_PATH

Search path Houdini uses to find plugins. It is relative to HOUDINI_PATH. @/plugin:&

HOUDINI_SCRIPT_PATH

Search path the Houdini uses to find python scripts @/scripts:/USD_INSTALL_ROOT/lib:&

HOUDINI_PYTHON_LIB

If you build USD with the python libs that ships with Houdini, you don't need to set this. However if you use a different python build, you need to set this variable so that Houdini runs with the python interpreter you built USD with.

 PYTHON_INSTALL/lib/libpython2.7.so

 

Houdini treats a few characters specially in configuration variables. See http://www.sidefx.com/docs/houdini/basics/config_env

For more information see our page on Advanced Build Configuration.

 

The Houdini USD plugins add these nodes. 

USD Import SOP Import USD geometry into Houdini
USD Output ROP Output geometry from Houdini as USD
USD Camera OBJ Import a camera specification from USD
USD Reference ROP Add a reference to a USD prim in a USD file
USD Sublayer ROP Add a sublayer to a USD file
USD Coalesce ROP Create a USD file that references a sequence of USD files that each contain 1 frame of data
USD Unpack SOP Unpack USD Packed Prims
USD Instance Prototypes SOP Add attributes to primitives to enable the USD Output ROP to write USD Point Instancer primitives
USD Export Attributes SOP Add attributes to primitives to control how the USD Output ROP writes geometry
USD Bind Proxy SOP Create a USD prim that contains render geometry and proxy geometry
USD Retime SOP Adjust the timing of a USD Packed Prim

All of these nodes have help cards. In addition there are a couple more documents.

A Tour of USD Houdini Primitives The Usd Import node will create USD Packed Primitives. This document describes these primitives and how to import and unpack them.
Writing USD from Houdini  
Houdini USD Example Workflow This document takes you through the process of writing USD overlays from Houdini.




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