Hi, what is the best practice to extend a node for example adding a tab with custom parms (buttons etc...) 1) For HDAs, I can do this via the type properties dialog. Extending the mantra node for example, changes are of course saved on the local OPlibdriver.otl and not on a central lib in $HSITE. I do not want to copy the modified local one there because every time the mantra node gets an update I would have to redo everything. And this only works for HDAs. 2) On a sphere node (non-HDA) I cannot edit operator types, but the Parameter Interface. But how is this saved? 3) monkey patch hou.Node.createNode with something like: Code: def customCreateNode(*args, **kwargs): # create node then do something with it like attaching new parms pass hou.Node.createNode = customCreateNode This is how it works in Nuke but its giving me errors I have to investigate... 4) regular callback (I could not find in the docs) 5) Other solution? Cheers Sebastian