some Nuke Python snippets

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Seeing as I’ve found very little reference for the use of python in nuke on the web I thought I’d create this post and add to it with little code snippets.

If anyone has some cool snippets to share please feel free to leave them in a comment below.

*lastupdated: 26 April 2012

delete all nodes that are not selected

s = nuke.selectedNodes()
b = nuke.allNodes()
 
for n in b:
    if n not in s:
        nuke.delete(n)

selects all dependencies (input nodes & their parents) from a selected node

a = nuke.selectedNode()
nodesToSelect = []
 
nodesToSelect.append(a)
def climb(node):
    # print node.name()
    for n in node.dependencies():
        nodesToSelect.append(a)
        climb(n)
 
climb(a)
 
for x in nodesToSelect:
	print x.name()
    # x.setSelected(1)

set all Read nodes to cache locally

for a in nuke.allNodes():
    if a.Class()=='Read':
        a['cached'].setValue(1)
        a['cacheLocal'].setValue(0)

print last frame of script

print nuke.root()['last_frame'].value()

create a backdrop based on selected Nodes

margin = 100
xpMax = nuke.selectedNode().xpos()
xpMin = nuke.selectedNode().xpos()
ypMax = nuke.selectedNode().ypos()
ypMin = nuke.selectedNode().ypos()
 
for a in nuke.selectedNodes():
    if a.xpos() > xpMax:
        xpMax = a.xpos()
    if a.xpos() < xpMin:
        xpMin = a.xpos()
    if a.ypos() > ypMax:
        ypMax = a.ypos()
    if a.ypos() < ypMin:
        ypMin = a.ypos()
 
bd = nuke.nodes.BackdropNode(bdwidth=(xpMax-xpMin)+margin, bdheight=(ypMax-ypMin)+margin) 
bd.setXpos(xpMin-margin/2)
bd.setYpos(ypMin-margin/2)

disable “postage stamps” on only “Read” nodes

for a in nuke.allNodes():
   if a.Class()=='Read':
       a['postage_stamp'].setValue(0)

disable “postage stamps” on all nodes

for a in nuke.allNodes():
    try:
        a['postage_stamp'].setValue(0)
    except:
        pass

“unhide” all nodes’ inputs – useful when receiving a sneaky comp/lighting script

for a in nuke.allNodes():
    try:
        a['hide_input'].setValue(0)
    except:
        pass

change the “first” frame of all selected nodes that are “Read” nodes:
(example changes the first frame to 1018)

for a in nuke.selectedNodes():
    if a.Class() == 'Read':
        a['first'].setValue(1018)

print a selected nodes’ methods

import struct
node = nuke.selectedNode()
for a in node['lookup'].animations():
    print dir(a)

print inputs (dependencies) of a selected node:

for a in nuke.selectedNode().dependencies():
    print a.name()

print outputs (dependents) of a selected node:

for a in nuke.selectedNode().dependent():
    print a.name()

find all the TimeOffset nodes in a Group called “Group2″, and change the value of each offset based on it’s position in the array of found time offsets

tos = []
for a in nuke.toNode('Group2').nodes():
	if a.Class()=='TimeOffset':
		tos.append(a)
for b in tos:
	b['time_offset'].setValue(tos.index(b))

set the ‘bbox’ for any selected Merge, Keymix & Copy nodes to “B”

for a in nuke.selectedNodes():
	classTypes = ['Merge' , 'Keymix', 'Copy', ]
	for n in classTypes:
		if n in a.Class():
			for p in a['bbox'].values():
				if 'B' in p:
					a['bbox'].setValue(a['bbox'].values().index(p))

remove all animation from a selected nodes

for a in nuke.selectedNode().knobs():
	nuke.selectedNode()[a].clearAnimated()

add keyframes – animate a mix

for a in nuke.selectedNodes():
	a['mix'].setAnimated()
	a['mix'].setValueAt(1,nuke.frame())
	a['mix'].setValueAt(0,(nuke.frame() - 1))

half the colour value of all the Constant nodes in a script

for a in nuke.allNodes():
	if a.Class() == "Constant":
		a['color'].setValue(a['color'].value()[0] / 2 , 0)
		a['color'].setValue(a['color'].value()[1] / 2 , 1)
		a['color'].setValue(a['color'].value()[2] / 2 , 2)

find all the transform nodes in a script, and if their input is a Crop, set the ‘scale’ value to be twice it’s current value (also checks if the scale is a list/array or a float)

for a in nuke.allNodes():
	if a.Class() == "Transform":
		if a.input(0).Class() == "Crop":
			x = a['scale'].value()
			if type(x).__name__ == 'list':
				a['scale'].setValue(x[0] * 2 , 0)
				a['scale'].setValue(x[1] * 2 , 1)
			if type(x).__name__ == 'float':
				a['scale'].setValue(x*2)

set all the gain values of all ColorCorrect nodes to be twice their current value

for a in nuke.allNodes():
	if a.Class() == "ColorCorrect":
		a['gain'].setValue(a['gain'].value() * 2)

print files with ‘mov’ in filename

for a in nuke.allNodes():
	if 'Read' in a['name'].value():
		if 'mov' in a['file'].value():
			print a['file'].value()

change font size of all “write” nodes in script

for a in nuke.selectedNodes():
	if "Write" in a['name'].value():
		a['note_font_size'].setValue(60)

create 20 constants with incrementing colour values

def makeConstants(amount):
	for i in range(amount):
		a= nuke.nodes.Constant()
		color= float( float(i) / float(amount) )
		a['color'].setValue(color)
makeConstants(20)

change the name of all Text nodes to contents the text “message”

for a in nuke.allNodes():
    if a.Class()=='Text':
        a.setName(a['message'].value())

##Expressions
(in an expression node) – alpha channel – if the y value of the pixel is even, make it 0, else make it 1 (for viewing fields?)
y%2==1?0:1

19 thoughts on “some Nuke Python snippets”

    • Hey Steve sorry for the delay, am currently doing some travel in Mexico.

      Try this:

      for a in nuke.allNodes():
         if a.Class()==’Read’:
             a['postage_stamp'].setValue(0)

      Reply ↓

  6. #Set Read Nodes Missing Frames Nearest Frame

    r = nuke.selectedNodes()
    for i in r:
    i['on_error'].setValue(“nearest_frame”)

    #Set Shuffle Nodes Write Their Incoming Channels Out

    s = nuke.allNodes(‘Shuffle’)
    for i in s:
    i['label'].setValue(“[value in]“)

    Reply ↓

  8. Great work Adam,
    being late for the party, found out your nuke forum now only.
    I have a query:
    How to get the paths in Read nodes and if anyone updated, how to reload that again in the scene, without reloading the whole scene

    Reply ↓

  9. getting paths of all read nodes
    for n in nuke.allNodes():
    if n.Class() == ‘Read’:
    print n['name'].value() + ‘ : ‘ + n['file'].value()

    Reply ↓

  11. # print all nodes with no connected output
    (maybe helpful to find dead branches end in high complex comps)

    for node in nuke.allNodes():
    if not len(node.dependent()):
    if not node.maxOutputs() == 0:
    print node.name()

    Reply ↓

  13. Can you help me please?! I’m having trouble duplicating a node through python.

    I have a group node with a few nodes inside. I also have 10 read nodes. What I would like to do it is select all my read nodes and have the script duplicate the group and place input to the read.

    any help would be greatly appreciated!
    Thanks

    Reply ↓

    • Hey Douglas!

      Thanks for the nice words!

      I had a quick look, try this (i´ll add it above):

      a = nuke.selectedNode()
      nodesToSelect = []

      nodesToSelect.append(a)
      def climb(node):
      # print node.name()
      nodesToSelect.append(node)
      for n in node.dependencies():
      climb(n)

      climb(a)
      for x in nodesToSelect:
      print x.name()
      x.setSelected(1)

      Reply ↓

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