Nuke: Launch command-line renders from the UI

I hacked up this script because I was frustrated with rendering in the Nuke UI, tired of typing out command-line render commands, and our renderfarm wasn’t alive yet. I’m posting it because I bet there’s other people in the same situation and I hope it can ease your pain.

This script launches a number of command-line render instances in the background and captures their output in log files which are saved to the same directory as the Nuke script. You are now free to keep working in the UI and have your renders happen in the background. You are also free to to launch 8 simultaneous command-line Nuke renderers and fully saturate your fancy 8-core MacPro.

It works in Nuke5.0v2 on OS X. Maybe it works on other versions and platforms. If so, I’d love to hear about it.






a script for launching single-core command-line nuke renderers

from inside the Nuke UI.


also saves log files of each instance's output to the same folder

where the Nuke script lives.


import re import nuke import os import sys

def launch_nukes(): a = nuke.knob("first_frame") b = nuke.knob("last_frame") start = int(a) end = int(b) incr = 1 instances = 1 _range = a+","+b p = nuke.Panel("Launch Nukes") p.addSingleLineInput("Frames to execute:", _range) p.addSingleLineInput("Number of background procs:", instances) p.addButton("Cancel") p.addButton("OK") result =

r = p.value("Frames to execute:")
s = p.value("Number of background procs:")
if r is None:
if s is None:
# this is the requested frame range
frames = r
# this is the number of instances to launch
inst = int(s)

(scriptpath, scriptname) = os.path.split(nuke.value(""))
flags = "-ixfm 1"

print ">>> launching %s nuke instances" % inst

# create a frame range string for each renderer
for i in range(inst):
    print ">>> generating range for instance %d" % i
    instRange = ""

    # separate ranges at spaces
    f = frames.split(" ")

    # separate individual start, end, and increment values
    for p in f:
        c = p.split(",")
        incr = 1
        if len(c) > 0:
            start = int(c[0])
            end = start
        if len(c) > 1: end = int(c[1])
        if len(c) > 2: incr = int(c[2])

        # re-jigger this range for this instance of the renderer
        st = start + ( i * incr )
        en = end
        inc = incr * inst
        new = "%d,%d,%d" % (st, en, inc)
        if inc == 1:
            new = "%d,%d" % (st, en)
        if en == st:
            new = "%d" % st
        if st > en:
            new = ""
            # add the re-jiggered range to the instances range string
            instRange = instRange + " " + new

    print ">>> range for instance %d is: %s" % (i, instRange)

    logFile = "%s/%s_log%02d.log" % (scriptpath, scriptname, i)

    cmd = "%s %s %s/%s %s > %s &" % (nuke.EXE_PATH, flags, scriptpath, scriptname, instRange, logFile)
    print ">>> starting instance %d" % (i, )
    print "command: " + cmd

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