Random Grade in Nuke / by Mauricio Ricaldi

One useful expression in Nuke is the random grade node, to simulate candles, fireplaces, lava, or anything that has random illumination.

Using the expresion : (random(seed,frame*frequency)*amplitude)+valueOffset

We build a gizmo based on the Grade, adding the expression on the gain.

Then we add seed, freq, amp and offset variables to a User tab.

Now we can tweak the curve parameter easily.

Here is the script for Nuke 9:

set cut_paste_input [stack 0]
version 9.0 v1
push $cut_paste_input
Grade {
 white {{(random(seed,frame*freq)*amp)+offset}}
 maskChannelMask rgba.blue
 name NoiseGrade
 selected true
 xpos -1276
 ypos 1894
 addUserKnob {20 User}
 addUserKnob {7 seed l Seed R 1 100}
 seed 2
 addUserKnob {7 freq l Frequency}
 freq 0.36
 addUserKnob {7 amp l Amplitude}
 amp 0.43
 addUserKnob {7 offset l OffSet R 0.1 2}
 offset 0.5
}