• object merge node: like object teleporter for far links

• ref:
  • 5 Ways to Organize your Network in Houdini 17.5 (IndiePixel3D) https://www.youtube.com/watch?v=w8yBoO-qvsk

• Python 3 and built-in PySide2
• houdini has its built-in qt library (PySide2), just import its own

  from hutil.Qt import QtCore, QtGui, QtWidgets

• houdini lic type check

  import hou
  lic = hou.licenseCategory()
  if lic == hou.licenseCategoryType.Apprentice or lic == hou.licenseCategoryType.ApprenticeHD or lic == hou.licenseCategoryType.Education:
      self.memoData['hda_ext'] = 'hdanc'
  elif lic == hou.licenseCategoryType.Indie:
      self.memoData['hda_ext'] = 'hdalc'

• core hou class
  • hou.HDADefinition (https://www.sidefx.com/docs/houdini/hom/hou/HDADefinition.html)

    cur_def.libraryFilePath() # get file path
    cur_def.version() 
    cur_def.description()
    cur_def.comment() # user
    # set
    cur_def.setVersion('2.1') 
    cur_def.setDescription(description) 
    cur_def.setComment('update details') # user
    # --- check
    node.type().definition() is None # check if current node is hda
    node.matchesCurrentDefinition() # check whether the contents of the node are locked to its type definition
    # --- action
    node.allowEditingOfContents() # unlock node (Allow Editing of Contents)
    node.type().definition().updateFromNode(node) #  save the contents of an unlocked node to the definition (Save Operator Type)
    node.matchCurrentDefinition() # reload defition (Match Current Definition )

• detect selected hda node info

  import hou
  if len(hou.selectedNodes()) == 1:
      node = hou.selectedNodes()[0]
      if node.type().definition() is not None:
          hda_file_path = node.type().definition().libraryFilePath()
          print(hda_file_path)
          definitions = hou.hda.definitionsInFile(hda_file_path)
          print(definitions)
          for d in definitions:
              print(str(node) + " name: " + node.type().name() )
              print(str(node) + " version: " + d.version())
              print(str(node) + " description: " + d.description())
              print(str(node) + " comment: " + d.comment())
              print(str(node) + " path: " + node.type().definition().libraryFilePath())
      else:
          print("Selected node is not a HDA")
  else:
      print("Please select 1 hda node")

• HDA = houdini digital asset
  • a set of node network functions as a core process
  • like model asset but instead of geo, it can be anything, like shading network, rig network or anything process.
  • once you add hda path into your houdini env, you can load it from tab menu like rest built-in hda asset (like nuke gizmo)
  • each hda is like a programming class, it has its unique type name like class name, all node of its class are instance of the node definition (its original content network)
  • once a instance of hda in the scene, it is like maya model reference, you can unlock and make additional changes (Allow editing of contents),
  • you can save the changes back into hda files (Save node type), or just keep changes in the scene
  • to revert back to original state, just select node, use (Match current definition cmd)
  • hda file can contain many hda assets, but recommed one asset for one hda file
  • hda asset can be inside houdini scene file, as Embedded instead of on a path file
  • nested hda need to be manually updated inside
  • ref:
    • https://www.tokeru.com/cgwiki/index.php?title=HoudiniHDA
• VHDA = versioned houdini digital asset
  • ref: create your own videos https://vimeo.com/458751335

• Houdini default menu source code:

  Houdini_VERSION\houdini\OPmenu.xml

  • related hda menu code

    #menu id: opmenu.create_hda
    kwargs["node"].canCreateDigitalAsset()
     
    #menu id: opmenu.vhda_options_create
    import hou
    import assettools
    node = kwargs["node"]
    if assettools.isSubnet(node):
        return 1
    else:
        return 0
     
    #menu id: opmenu.vhda_create
    import hou
    import assettools
    node = kwargs["node"]
    assettools.createNewVHDAFromSubnet(node)

• Houdini python API library path:

  Houdini_VERSION\houdini\python3.7libs\
  #hda related files
  assettools.py
  C:\Program Files\Side Effects Software\Houdini X\houdini\python3.7libs\assettools.py

• node > definition > all info related
• node info

  # node
  if len(hou.selectedNodes()) == 1:
      node = hou.selectedNodes()[0]
  # node info
  print(str(node) + " name: " + node.type().name() )
  print(str(node) + " locked: " + node.isLockedHDA() )

• definition

  # definition
  if node.type().definition() is not None:
      hda_def = node.type().definition()
   
  # definition info
  print(str(node) + " path: " + hda_def.libraryFilePath() )
  print(str(node) + " version: " + hda_def.version())
  print(str(node) + " description: " + hda_def.description())
  print(str(node) + " comment: " + hda_def.comment())
  # definition operation
  cur_def.isInstalled()
  cur_def.save(tmp_filepath, template_node=node)

• hda file

  # hda file
  hda_file_path = hda_def.libraryFilePath()
  definition_list = hou.hda.definitionsInFile(hda_file_path)
   
  # check hda file list loaded in memory
  loaded_hda_file_list= hou.hda.loadedFiles()
  print('\n'.join(loaded_hda_file_list))
   
  # hda file load/unload
  hou.hda.installFile(hda_file_path)
  hou.hda.uninstallFile(hda_file_path)
  # hda file reload
  hou.hda.reloadAllFiles(True)

* check and remove HDA

# hda_file_path: the path of hda file
cur_path = hda_file_path
if os.path.isfile(cur_path):
    # uninstall for safe
    definitions = hou.hda.definitionsInFile(cur_path)
    is_installed = 0
    for d in definitions:
        if d.isInstalled():
            is_installed = 1
    if is_installed:
        # Uninstall the HDA
        hou.hda.uninstallFile(cur_path)
    # remove action
    # os.remove(cur_path)

• [Houdini official] Houdini Digital Assets | 1. Introduction to HDAs (2021)
  • https://www.youtube.com/watch?v=ybk8XWBnO4o