Technique Section

To Merge here: App Nuke

https://github.com/adrianpueyo/KnobScripter
- a standalone python editor for nuke, but can be extended

pyside for nuke https://www.youtube.com/watch?v=ltODr920bpA
https://github.com/fredrikaverpil/pyvfx-boilerplate
http://community.thefoundry.co.uk/discussion/topic.aspx?f=190&t=102688
https://docs.thefoundry.co.uk/nuke/63/pythondevguide/custom_panels.html
fxphd NUK230 PySide for NUKE
http://tylerart.com/sketchbook/

Method 1: nuke environment setting, use that to let nuke load its init.py and menu.py there
```
NUKE_PATH
D:/myPath_for_nuke
```
Method 2: edit ~/.nuke/init.py, and menu.py, to load your custom init.py and menu.py at other location
```
import nuke
nuke.pluginAddPath('D:/myPath_for_nuke')
```

system detection

import sys
osMode = 'other'
if sys.platform in ['win32','win64']:
    osMode = 'win'
elif sys.platform == 'darwin':
    osMode = 'mac'
elif sys.platform == 'linux2':
    osMode = 'linux'
print("OS: {0}".format(osMode))

nuke detect GUI mode

import nuke
nuke.env['gui'] # print 1 or 0

nuke will auto run all the init.py in the path directories before launch

init.py

import sys
if nuke.NUKE_VERSION_STRING.startswith('9'):
    nuke.pluginAddPath('./9.0') # relative path
    sys.path.append('D:/myOtherPythonModulePath') # abs path

launch nuke with custom python initial script
```
Nuke.exe replaceWritePaths.py other_args
```

menu.py file is another place for you to put menu related script, it is like init.py but more for menu creation

# nuke main menu object
nuke.menu('Nuke').addCommand('subMenuFolder/menuItemName','print("your python cmd example")', icon='/iconPath/toolName.png')
 
# nuke gizmo menu object
cur_menu = nuke.menu("Nodes").addMenu("myGiz", icon="myGizmo.png")
cur_menu.addCommand('subMenuFolder/menuItemName','print("your python cmd example")', icon='/iconPath/toolName.png')
 
# custom image formats
nuke.addFormat("1280 768 0 0 1280 768 1 HD 1280 Square")

the event driven functions that nuke will execute when the event happend. You can put those event function in init.py file, which nuke reads after launch. (in both gui and cmd mode)

nuke before render event example

nuke.addBeforeRender(funcNameToDoBeforeRender) # it pass the write node as nuke.thisNode

render the all write node in script

"C:\pathToNuke\NukeVersion.exe" -nukex -i -F 1001-1020 -x "R:/pathToScript/myNukeScript.nk"

render the Defined Write Node

"C:\pathToNuke\NukeVersion.exe" -nukex -i -X ThatFinalWrite "R:/pathToScript/myNukeScript.nk" 1001-1020

menu creation with one-line and auto creation if not exist

# it automatically create xTool menu in menubar, 
# and create "CompHelper" menu item that call function string, with shortcut and icon 
import sys,os;myPath=r'D:\Dev\CompHelper'
myPath in sys.path or sys.path.append(myPath);import CompHelper;
cmd = nuke.menu('Nuke').addCommand("xTool/CompHelper", 'CompHelper.main()',icon=os.path.join(myPath,'icons','CompHelper.png'))
cmd.setIcon(os.path.join(myPath,'icons','CompHelper.png'))

save script

nuke.scriptSave( outScript )
 
curScript = nuke.toNode("root").name()
nuke.scriptSaveAs("/scratch/snapshot.nk")
nuke.scriptSaveAs(curScript)

set knob to readonly/locked

knob.setEnabled(False)
 
# lock with a flag
nuke.selectedNode()[knob].setFlag(nuke.DISABLED) 
nuke.selectedNode()[knob].clearFlag(nuke.DISABLED)

common menu operation codes

# top menu and side bar menu obj
nuke.menu("Nuke")
nuke.toolbar("Nodes")
 
# add menu and add cmd obj
menubar = nuke.menu("Nuke") # main menu bar
my_menu = menubar.addMenu("MyMenu") # menu object
my_menu.addCommand("Test","print('Test')") # menu item; subFolder/Test for subfolder cmds
 
menubar.addMenu("MyMenu") # Important, without a var to hold it, it becomes menuItem object instead of menu obj
 
# get items of a ui object
# list direct child UI object
menubar.items()
# return menu child with that name
menubar.menu('MyMenu')
# return menu or menuItem child w that name
menubar.findItem('MyMenu')
# loop method of listing
name_item_child_list = [ [cur_item.name(), cur_item] for cur_item in menubar.items() ]
print(name_item_child_list )

ref:

root first frame and last frame

start = int(nuke.Root().knob('first_frame').value())
end = int(nuke.Root().knob('last_frame').value())

get and goto frame

curFrame = nuke.frame() # get
nuke.frame(1002) # goto

Common maya like file operation, like Import/Edit file, and export selected/ save file as.

# import file to viewport
nuke.nodePaste(in_filepath.replace('\\', '/'))
# edit File
nuke.scriptOpen(in_filepath.replace('\\', '/'))
# save Selected as File
nuke.nodeCopy(out_filepath)
# save file as
nuke.scriptSaveAs(out_filepath)

get current script file path

full_path = ''
try:
    full_path = nuke.scriptName()
except:
    nuke.message('No path found.')

set a nuke node default

nuke.knobDefault( 'Write.afterRender', 'import myFun;myFun.some_action()')

nuke script's root root
```
root = nuke.thisNode()
```
nuke callBack function to access current call node
```
thisNode = nuke.thisNode()
```

read

my_node = nuke.createNode('Read')
my_node['file'].fromUserText('/path/to/your/file.mov')

get selected nodes with type filtering

selected = [x for x in nuke.selectedNodes() if x.Class() == 'Read']

find all read nodes

nuke_readNodes = [x for x in nuke.allNodes(recurseGroups=True) if x.Class() == 'Read']
self.memoData['nuke_path_list'] = [os.path.normpath(os.path.dirname(x['file'].value())) for x in nuke_readNodes]

find all write nodes

def getNodeByClass(nodeClass, startNode):
    if startNode.Class() == nodeClass:
        yield startNode
    elif isinstance(startNode, nuke.Group):
        for child in startNode.nodes():
            for foundNode in RecursiveFindNodes(nodeClass, child):
                yield foundNode
allWriteNodes = [w for w in getNodeByClass('Write', nuke.root())]

render write node

# set after render python script
cur_node.knob('afterRender').setValue("WriteToMov()") # call a python function after done rendering
# call render
nuke.execute( nodeName, firstFrame, lastFrame )

ref: https://www.thefoundry.co.uk/products/nuke/developers/63/pythondevguide/command_line.html

bake keyframe animation
- ref: https://docs.thefoundry.co.uk/nuke/63/pythondevguide/animation.html

add knob callback

node.knob('knobChanged')
nuke.addKnobChanged(function)
nuke.removeKnobChanged(function)

Nuke Tcl Expression is not python, but nuke's own syntax for UI starts and node copy,paste,save as nk files.
- it functions like Maya mel expression but it doesn't show the final result in attribute panel but the formula, while it does show the result in node editor view.
- it use [] to contain a element, and operation is inside it with parameters and spaces.
the Tcl expression support data operation, logic operation, regex, and python script.
- tip example: http://thoughtvfx.blogspot.com/2012/12/nuke-tcl-tips.html
- auto write node: http://www.nukepedia.com/written-tutorials/how-to-build-an-automatic-write-node
ref:
- https://docs.thefoundry.co.uk/nuke/105/pythondevguide/
- http://www.nukepedia.com/tcl/tcl-reference
- http://www.nukepedia.com/tcl/value-vs-knob-command
- nuke help/Documentation/Tcl/grouptclexpressions.html#gafe083716d50b3fb4057e519961b9235c

Replace Single Line String to Multi Line Display

put noteStr text input value into current message text block value, the single line format as “test / better one / best line” as
```
[regsub -all " / " [value noteStr] "\n"]
```
it is useful to put [argv 8] like in the noteStr value, as cmd arg has to be in single line format

Use Express to Link StrValue to IntValue

create a user text input knob, then use expression to link int knob to this text knob, and use [argv 7] like cmd arg to drive text value then updating the int value. (since int knob seems can't set as [argv 7] like)

example

# file attribute expression:
[value rdir]/finals/[value shot]/NK_[value shot].%03d.dpx
# get evaluate result
print (nuke.thisNode()["file"].evaluate())

# mix python in tcl
file "\[value nas_root]/\[value project]/\[value seq]/zup_renders/Comp/\[value RenderType]/\[value shot]_[value FileName]_v[python {str(int(nuke.thisNode()['ver'].value())).zfill(3)} ]/\[value shot]_[value FileName]_v[python {str(int(nuke.thisNode()['ver'].value())).zfill(3)} ].####.\[value file_type]" 

# use cmd
 knobChanged "\ncur=nuke.thisNode()\npathA = \[ cur\[each].value() for each in \['nas_root', 'project', 'seq'] ]\npathB = \['zup_renders/Comp', cur\['RenderType'].value() ]\nsegC = cur\['shot'].value()\nif cur\['FileName'].value() !='':\n    segC+='_'+cur\['FileName'].value()\nsegC+='_v'+ str(int(cur\['ver'].value())).zfill(3)\npathD = \[ segC+'.####.'+cur\['file_type'].value() ]\ncur\['file'].setValue( '/'.join( pathA + pathB + \[segC] + pathD ) )\n"

TCL and Python Expression that trigger by frame reading error, as a way to detect error frame like corrupted exr, ref: https://forums.cgsociety.org/t/read-node-on-corrupt-frames-workaround/1650526/2
1. create a user integer knob on Read node
  1. set its value expression (Python)
```
nuke.thisNode().error()
```
  2. or set its value expression (TCL)
```
[value error]
```
2. or create a user integer knob on Read node downstream connected node and
  1. set its value express (Python)
```
nuke.thisNode().input(0).error()
```
  2. or set its value express (TCL), which take its topnode
```
[value [topnode].error ]
```