Python in Houdini

  • PySide2 in Python 2.7 is built-in with houdini
  • Python Access method:
    1. Python background shell:
      • Alt+Shift+P: bring out float copy of Python Shell
      • other Python shell can be brought out from panel menu
      • houdini can have multiple independent python shells inside, unlike single ScriptEditor in Maya
    2. Python Source Editor (for temp test use only)
      • works more like ScriptEditor's editor panel, only output to current top Python Shell.
      • its function code is wrapped in a namespace “hou.session”
      • its function code is stored with the hip file (it's file session based, not globally)

Technique Section

Tutorial Reference

UI operation

  • alert message 
    hou.ui.displayMessage('cool')

setting

  • get current frame 
    hou.frame()
  • add variable to hou's global() dictionary 
    hou.expressionGlobals()['myVal'] = 2018

Network Editor

  • get network editor 
     net_edit = hou.ui.paneTabOfType(hou.paneTabOfType.NetworkEditor)
  • move node 
    curNode.setPosition([0,0])
  • color node 
    curNode.setColor(hou.Color(1,0,0))

Node Operation

  • Node access 
    curNode = hou.node('/obj/geo1') # get node by name path like in Nuke(hou.SopNode)
curNode.name() # node name
curNode.path() # node path
curNode.children() # node's inside nodes
curNode.parm('tx').eval() # node's attribute's value (hou.Parm)

Houdini Asset

  • parm template operation 
    print( hou.parm('/obj/assetNode/attr').parmTemplate().asCode() ) # get build script
 
tabs = asseNode.parmTemplateGroup().entries() # get list of tabs of attr
parmList = tabs[0].parmTemplates() # all the parm entries

Houdini HScript

  • Hscript in Houdini = Mel in Maya, you can warp them around similarly
  • you can use Hscript in python as well
    • hou.hscript()
    • hou.hscriptExpression()
    • hou.expandString() # get hscript variable in python
      • you can also get local variable with lvar()
  • in houdini Python shell, you can directly access hscript by type % at start

Houdini inline C++

  • you can create a in-line one-time compile C++ code in a python script to speed up heavy-calculation part

Houdini RPC

  • socket based XML passing and commanding
  • new one called HRPyC, old one is houxmlrpc

Houdini Python lib

  • default by python versions: $HFS/houdini/python0.0libs

Pipeline